Street Fighter 6 is a surprisingly balanced game, so there isn't any character who is at a real disadvantage against the vast majority of the cast. Some of the launch characters, however, can be a pain to deal with at any level.
Among the characters that can be difficult to fight is JP. The main villain of the game is an oppressive zoner like we have never seen before in the series, so it's not surprising to see many fall under his special techniques. However, there are ways to beat these techniques.
JP's main zoning tool is Triglav, his ground spike projectile. The move is incredibly fast, and if just blocked, it will obliterate your Drive Gauge, and going into Burnout against any character is bad news, even more so against JP, who can deal a lot of chip damage safely. As such, no matter which character you are using, you will want to parry all of JP's projectiles, including Triglav. While parrying them to prevent your Drive Gauge from becoming empty is good enough, you will want to Perfect Parry them for a very good reason. As you may already know, perfectly parrying projectiles allows you to cancel the parry animation into any move, including Drive Rush, so if you manage to Perfect Parry a Triglav attack, you can close the gap with JP, making it more difficult for him to execute his gameplan. In addition, you can also dash forward after blocking or parrying Triglav to gain some space safely. Make sure to mix up your answers to Triglav, as an Overdrive Triglav can punish your dashes.
Triglav, however, is only one of JP's ranged attacks that can make your time miserable in Street Fighter 6. His Torbalan fireball is not just a fireball but a mix-up as well since, depending on the button pressed, it must be blocked either crouching or standing. Perfect Parrying one of them is one of the ways to counter them, but there are a few other ways to deal with them and easily close the gap with JP. One of them is to use Drive Rush to go through the fireball, as its hitbox becomes active only after it has traveled a certain distance. Characters with fast Drive Rushes that cover a lot of distance, such as Dee Jay's, can easily go through the fireball, but even characters with slower Drive Rushes can get through with the correct timing.
JP's Torbalan can also be neutralized by specific character techniques. Almost every character in the game has a specific move that can be used to close the gap and beat this annoying fireball. Speaking about the characters I main, Blanka, for example, can either use medium or heavy Rolling Attack or use Drive Rush and his down forward heavy punch slide to reach and punish JP; Ken, on the other hand, can go through the Torbalan with Dragonlash Kick, or even get to JP with a well-timed run into Shoryuken, although this is way more risky, as you will be eating a Punish Counter combo if you read your opponent wrong; Luke's Overdrive Avenger can absorb one hit for the duration of the run, but you need to space it right, as both follow-ups are unsafe on block. All of these techniques, if not used properly, can get punished, but what you will want to achieve with them is to condition JP not to use Torbalan freely to pressure you.
Dealing with the other ranged attacks JP has at his disposal requires mostly one thing: patience. Departure, his special move that places voids that can either unleash a spike or let him teleport to its location, is essentially a mix-up, so you will have to understand your opponent's tendency and see how they use the move during the match. Embrace, a long-range command grab, is very slow and can be easily avoided by jumping, so keep your cool during any exchange, and use the animation and sound cues to recognize the technique and react accordingly.
One final ranged attack to look out for is JP's Level 2 Super, Lovushka, which unleashes four tracking projectiles that hit high, overhead, low, and overhead again, so you must block accordingly to avoid getting hit. While parrying is a decent answer for this attack, as you do not have to worry about the high, low mixup, JP can throw you between attacks, but getting thrown to end the special may be a good tradeoff in certain situations. Also, if Lovushka is activated raw, you can Drive Rush to avoid getting pinned down by the ghosts, as there's a gap from activation to the super actually becoming active. If it is activated after an attack string, the only things you can do are blocking and parrying or risk using an invincible reversal if JP is close, as he may attempt to hit you low when the overhead projectile is active or throw you. While most of JP's ranged attacks cannot be used for the duration of Lovushka, he can still use Departure and try to mix you up, but the best answer for this is once again parrying. You may end up getting thrown, but it may be better than taking a full combo.
One final thing to be mindful of in Street Fighter 6 when fighting against JP is his Amnesia reversal, whose Overdrive version can counter almost anything, even throws and command grabs. If you see your opponent using it repeatedly, you can either neutral jump, walk back slightly, or use Overdrive projectile attacks, which are generally safe on block, as Amnesia cannot counter them. Once you have conditioned your opponent not to throw Overdrive Amnesia out on every wake-up, you can finally pressure JP without having to worry too much about it.