You can get a replacement rubber part for under $15 - takes a couple minutes to swap out. I did this recently on my HH pedal and it works perfectly again.
SENSOR ACTUATOR Fits ROLAND FD-8,... https://www.amazon.com/dp/B07N72FWC7?ref=ppx_pop_mob_ap_share
FD-8 has a well known issue with a critical rubber part stiffening over time and causing the Hi Hat to remain open. It costs about 20 bucks on amazon to replace. Rubber Actuator
I replaced mine and it worked pretty well, but I just recently upgraded to an FD-9 and, while better than the FD-8, it is still a little frustrating on catching nuanced, partially open hi hats.
This is a 20/200/2000 dollar problem and I think it just boils down to what you are willing to spend. If you've got the money, I'd just solve the problem and get the TD17 kit. I personally don't think the FD-9 is 180 dollars better than the FD-8, and I'm probably going to upgrade eventually. Buy once cry once... sigh.