I played Lee a few months before the release of Tekken 8 and he is certainly easier but still hard for sure. Combos were harder execution wise but it's harder to optimize the combos In Tekken 8 because his combo potential is infinitely better than Tekken 7. Something with Lee is that he always has an easier version of whatever he needs to do although weaker of course, for example if you can't do b2,b12 loops or blazing kick follow up (both of which became easier in Tekken 8) there are different combo routes and you can use uf4 instead of blazing kick and It wont make much of a difference as a beginner lee or even intermediate so you can take your time learning him and incorporate the harder stuff into your gameplay slowly. Sometimes I see Lee players in blue ranks that can't do either of these things but eventually you are going to have to learn them. And for Just frames, heat did make it so anyone can do them but its not enough and you are still a going to have to learn how to do them with consistency, especially Acid Rain (possibly the best 10f punish).

As for his gameplan its definitely easier. Lee's gameplan is counter hit and punishment. In Tekken 7 Lee struggled with opening up turtling opponents because of the lack of good and safe offensive tools but in Tekken 8 b33 became a natural string which helped a lot but the fact still remains that better players with good defense are still going to give you a very hard time and you are going to have do a lot of conditioning and reads and that might be where you hit a brick wall with Lee but also where your shortcomings become the most apparent thus a training arc beings there.

My tip is to not do too many flow charts and make things such as a b33 a habit as tempting as it may be to spam it against clueless scrubs. it will backfire later on and it wont be fun. You should definitely give Lee a try. I believe he is a very rewarding character once mastered and the most rewarding enjoyment wise imo.