Maintaining semi-erect penis through jelqing session

Been doing PE for about two weeks (newbie routine). I do 10 minutes of jelq, with a stopper near by, but I seem to lose erection within 30-90 seconds of jelqing. I have to watch porn and masturbate for few seconds to gain like 80% erection, and then I continue the time from the point I lost erection, and presume jelqing while my penis gradualy loses erection, and repeat the proccess till I get to 10 minutes.
Usualy I don’t have problems with my erections, but I relay struggle to keep my member aroused enough without porn + brief masturbation sessions every minute or so, and because of this I struggle to do the routine in the shower, and have to do it in my room, which is much less comfortable for me. Any tips?

Just in case, my routine consists of 10 stretches (40 seconds each), 10 minutes of jelqing 2 days ON 1 OFF, and about 100 kegels everyday.

I am the opposite. I get raging hard on shortly after doing my stretches. So my Jelq level is always around 80%. I always have to do squeezes to ease it off.

For your problem, try use your PC muscle and do more kegels during the Jelq. It may help to keep yourself hard

You mean squeezing the PC muscle while jelqing?
Will try next time