There's a very similar question: How can I train my cat to not jump on the kitchen counters?, but as you mention, you've tried common methods.

Cats are more likely to go on the counters when they are hungry or bored. Make sure those are taken care of- it's more difficult when you put the cat on a diet, but that usually isn't a problem in the kitten/young cat stage.

I've brought up several cats. One was.. problematic. I love him partly because he has a strong personality. With that cat, we tried:

• double-sided tape on the counters. would jump past several rows of tape (or directly on it) and lick it. He still loves the taste of packing tape.
• foil on the counters. Would jump past it or onto it and then saunter past. Covering the entire counter was problematic for us humans.
• fishing line, in many rows, as a "fence". Would jump through 1" (20mm) gaps or jump over 5-6 rows (6" / 12cm).
• coins in an aluminum soda can. We shook it until the aluminum was weakening and splitting from the coins. He'd jump down whenever we reached for the can but would jump up, especially if none of us were monitoring him.
• "motion alarms" on the countertops. These were super-sensitive- they would scream when we were walking near the counter, but he was able to jump onto the counters lightly enough to avoid tripping them.
• spray bottle. Similar to the above.
• throwing things at him. I tried to keep small objects nearby, but it was based on me being in the room to observe him and on the accuracy of my throw. So it was a big fail.
• yelling/clapping. I still use this ("HEY!" in a stern voice) and it brings instant shame to a somewhat-trained cat. But it didn't "set" the behavior in this young and headstrong cat.

Our last resort was to use an electric training collar, like the "invisible fence" dog collars. I think we used the Pawz Away barrier collar. It had little radios that look like a smoke detector- two, on a low setting, covered our counters without affecting the normal path of the cat. We used the collar on ourselves before on the cat- when you got near, it would beep and then zap.

It took perhaps a month for the cat to learn. We had to adjust the radio levels and the tightness of the collar, as a too-loose collar wouldn't contact him for the zap. But after a month he quit going on the counter several times during the day and night. We had to do a retraining session perhaps two months later. He is eight now and still behaves that rule (with a few exceptions per year.. we've learned not to leave cream cheese frosting out!).

I don't feel great about using a training collar on a cat, especially an indoor cat. I'm a little ashamed about it. However, it worked after trying many different options.

(in retrospect, naming him "A Boy Named Sue" might have been my first mistake)

There's a very similar question: How can I train my cat to not jump on the kitchen counters?, but as you mention, you've tried common methods.

Cats are more likely to go on the counters when they are hungry or bored. Make sure those are taken care of- it's more difficult when you put the cat on a diet, but that usually isn't a problem in the kitten/young cat stage.

I've brought up several cats. One was.. problematic. I love him partly because he has a strong personality. With that cat, we tried:

• double-sided tape on the counters. would jump past several rows of tape (or directly on it) and lick it. He still loves the taste of packing tape.
• foil on the counters. Would jump past it or onto it and then saunter past. Covering the entire counter was problematic for us humans.
• fishing line, in many rows, as a "fence". Would jump through 1" (20mm) gaps or jump over 5-6 rows (6" / 12cm).
• coins in an aluminum soda can. We shook it until the aluminum was weakening and splitting from the coins. He'd jump down whenever we reached for the can but would jump up, especially if none of us were monitoring him.
• "motion alarms" on the countertops. These were super-sensitive- they would scream when we were walking near the counter, but he was able to jump onto the counters lightly enough to avoid tripping them.
• spray bottle. Similar to the above.
• throwing things at him. I tried to keep small objects nearby, but it was based on me being in the room to observe him and on the accuracy of my throw. So it was a big fail.
• yelling/clapping. I still use this ("HEY!" in a stern voice) and it brings instant shame to a somewhat-trained cat. But it didn't "set" the behavior in this young and headstrong cat.

Our last resort was to use an electric training collar, like the "invisible fence" dog collars. I think we used the Pawz Away barrier collar. It had little radios that look like a smoke detector- two, on a low setting, covered our counters without affecting the normal path of the cat. We used the collar on ourselves before on the cat- when you got near, it would beep and then zap.

It took perhaps a month for the cat to learn. We had to adjust the radio levels and the tightness of the collar, as a too-loose collar wouldn't contact him for the zap. But after a month he quit going on the counter several times during the day and night. We had to do a retraining session perhaps two months later. He is eight now and still behaves that rule (with a few exceptions per year.. we've learned not to leave cream cheese frosting out!).

I don't feel great about using a training collar on a cat, especially an indoor cat. I'm a little ashamed about it. However, it worked after trying many different options.

(in retrospect, naming him "A Boy Named Sue" might have been my first mistake)