Yeah fleshlights can feel pretty good sometimes, I’ll give you that. But I’m a little surprised you’ve gone 3 years without seeing improvements though. Sounds like you’re just using them solely for your pleasure ;) . Have you tried going really slow at first, like barely moving if you get close? Then work your way up to faster when you get more control.
A big thing for me is edging, but relaxing and staying away from feeling much pleasure or getting anywhere near orgasm for at least 20-30 minutes. I want to be sure I can last longer before I worry about myself.
I sometimes go through premature ejaculation phases when I get too many blowjobs (I train myself to come fast because I feel bad about getting my gf’s jaw too sore!) or if I go a week or more without sex. Then after a few edging sessions of 30-40 minutes, I can usually train myself to have plenty of control.
Anyways good luck with the routine, stay consistent!