The blue one it going to take a bit of working up to.
There are quite a few slimline dildos in the shop though and something like this is always an option. I cant recommend you anything specific sadly as im female and prostate play not something ive tried with a partner.
Searching the reviews for “prostate” or “p spot” is usually a good way to spit out the ones you want though
There is a cracking p spotting thread on here, give me a sec and i will find it. It has good recommendations
@Joe18 here we go. Lots of good info in there