@Pyndle
As someone who started with a Nikonos IV (then a V), then a couple of housed Nikon film cameras, then several early Nikon DSLR's, and now shooting with a housed D850, I understand and empathize with what you are feeling.
When I get to this point I tend to just leave my camera at home/on the boat. Both my son and daughter shoot underwater (my son uses my old D500 and my daughter shoots with an A7RV) so I help them find subjects and spot for them.
There are a couple of times where a destination was going to be hard to carry my large rig, so I have also experimented with smaller cameras, housings, strobes, etc. Nothing has really made much sense, including shooting with a phone in a housing (although of all the options, this one is clearly getting closer).
I will say that a TG6 (for macro) with a single strobe is absolutely a legitimate choice. For a certain set of subjects this is starting to get close to what you can achieve with a larger system. The other comment I'll add is that when I want to go small, I mount a single strobe on the top of my D850 housing, use the 60mm lens and flat macro port. This is a great set up for shooting macro (used this a number of times in places like Lembeh and Anilao). This is significantly smaller than my wide angle set up.
I'm also not sure about the issue with rinsing your gear. I've been shooting with housed systems for ~20 years. When I come back from a dive, I put it in the rinse tank for ~5 min (usually while I get out of my wetsuit) and then take it out and dry it off when I'm ready.
Come to think about it, the last 4 trips I've been on the dive staff have carried my camera from the boat and put it in the rinse tank (on our recent trip on the Arenui LOB they also dried it and moved it back to the camera station afterwards). I haven't had to worry about rinsing much recently.
Traveling with everything is an issue. When our family travels together we bring 3 housings, 3 cameras, 5 strobes (2 for me, 1 each for our kids, and 1 spare), batteries for all of these, ports for both macro and wide angle for all three systems, focus lights, etc. It's a load, but we've gotten it down to one checked camera bag (and then each person carries their own camera & housing in a carry on).
I can dive w/out a camera and still enjoy a dive, but I choose to continue to dive with a camera because even after years of shooting, I still enjoy the creative process.
Last - my wife is the only one of us that doesn't shoot with a large camera - she uses a GoPro (now the 11). Even with the macro flip down filter, this is a poor substitute for shooting small subjects (but it is awesome for capturing big stuff like schools of fish, sharks, turtles, etc.)
BTW - if you are having an buoyancy issue with your dome port it's likely because it's acrylic. This is an issue will all acrylic domes - the easy solution is to get a glass dome. For some this may be a cost thing, but it does solve the issue (I have 2 acryllic domes that I don't dive with any more because of the annoying constant tilting up of the port when I dive. I got tired of fighting this, or weighing it down with weight).