Vaseline can increase the chances of a yeast infection in a lot of women. I use Chamois Butt’r Her’ (developed by a woman sports physician) for it’s anti-inflammatory, antiseptic properties and with a ph balance specifically for women. It also washes away easily with soap and water. I always wash down there with a natural tea tree oil soap after a long ride or when i feel a problem just starting. A saddle search can be frustrating especially since we have different bodies, riding positions and needs. When I find one that works I buy a few of that model. A good fitter, my preference is a woman, can help a lot in getting the bike position and a saddle and its position that works well. So I’d say a good bike fitting, a good chamois cream, a quality seamless chamois should help especially with someone who rides as much as you do.

Good luck in working it out Ellie and welcome to the forum.