Not evolving in my workout

Hello everyone :)

It's my second topic this week 😮 I promise it will be the last lol.

Something just bugging me these days... I've been working out with FB since almost 3 years (maybe more tho I stop the counting xD) and, yes I can see that somehow I did improve myself, but after all I still struggle and still didn't improve my range of weight.

For example, in HIIT session, I'm still struggling hard, I can't for example do 20 sec of jump squat straight because it hurts. I wish I could improve that but how ?

For strength training it's kinda the same, for exemple I squat with 5 kg per hand since forever and I still struggle with that ! I feel like I'm stuck.

Btw I train 6 days a week (but one day is only stretching 😻).

Thank you !

Edited