I never found any kind of money belt that truly felt secure until I "discovered" a step-in one originally designed for runners. The one I have now is this StashBandz one in black. Do I need to say that you do not wear it outside your clothes like the picture shows? Everything that I'd need for an identification or financial emergency goes in it.
I also haven't experienced a hot or sweaty money belt, including this one. The way I wear it may or may not be the reason. From the skin out: skin->bra->shapewear tank->StashBandz->panties->pants->top. So the StashBandz never touches my skin. If long enough, a regular tank top could sub for the shapewear tank. BTW, many people who wear shapewear tanks wear them incorrectly. They are supposed to be worn under the panties, not over them.
I am not a fan of any kind of heavy, wire threaded, RFID cross-body bag. I think they're a solution looking for a problem. I also think that so-called lockable zippers that use lobster claw style "locks" can give people a false sense of security. If it's easy for you to press to open them, it's easy for a pickpocket to do it too. I'm always amused by the pictures that show lobster claw hardware or easy press carabiners being used to secure a bag to a chair. That adds about a second to how long it might take for a thief to grab the bag and run.
I do like a simple cross-body bag with no exterior pockets that I can use small screw type carabiners or split keyrings to secure the zipper with. I put those on every zipper I can on my roller bag, personal item or purse. My latest purse find is this "round" one from UNIQLO. I got it in black and have been using it for a few months now. If you go to the link, you'll see how some people wear it high on the chest. I wonder how long that positioning lasts?
Fortunately, the strap is long enough to wear it like a normal cross-body purse. Much to my surprise it holds a lot more than I expected it would. Whether at home or traveling I slide my cross-body bag down so that the strap is around my waist and make sure that the purse itself is in my lap, between my legs, under one thigh, or next to a wall -- never on the exterior side of a table.
All that works well for me. Something else might work well for you. But I agree that a waist or chest bag, especially if stuffed, is a prime target for pickpockets and that we should never put all our financial and id eggs in one bag of any kind.