Speedoswimmer you look slim and fit in your white Speedos and should look good in just about anything. Is the line up the front a seam or just the waist tie cords tucked in ? If you aren't going to tie them untuck them and let them hang loose.
Your search for maximum penis exposure while wearing swim briefs will cause complaints and get you into trouble with Lifeguards in a public pool, balance your need to swim to keep fit with your desire to show yourself off, don't upset other people. In the summer head for quiet beaches, lakes and rivers where you can wear less without upsetting anyone and enjoy the sunshine on your body.
To me the ultimate classic racing 2" swim brief is the Arena Santamaria in yellow, I'm wearing them now for you:
https://www.amazon.co.uk/Arena-SANTA...tamaria+yellow
Although you have said you wish to wear 2" swim briefs I would suggest that you try a 1" swim bikini with a pouch for your collection, although you might not be able to wear them in your local pool. Since you seem to like unlined and untied might I suggest Brave Person, perhaps in pink or white:
https://www.ebay.co.uk/itm/Mens-Sexy...53.m1438.l2649
If you really want to show off your bulge wear a thong, the eye is draw to the pouch once nearly everything else is naked. Desmiit make a nice safe yellow swim thong with a waist cord:
https://www.ebay.co.uk/itm/Mens-Desm...frcectupt=true
but if you want to go further and have an unlined swim thong with no waist cord go back to Brave Person:
https://www.ebay.co.uk/itm/Mens-Sexy...rhucsgUkJ1V_pw
PS. You might like these:
https://www.ebay.co.uk/itm/Pouch-Men...-/401678950740