I also only play WW2, so usually I don’t play above 6.7 but I make an exception for the Maus. I honestly don’t share your take that it can only be used for goofs. I’m a very average player and can still get very good mileage out of it in RB (and in SB, it’s a beast).
A few things you might find interesting:
I take somewhere around 20 rounds for the main gun and 40 for the coax. I usually bring ten PzGr 43, ten 12.8/8.8 Pzgr. TS, thirty Hl.Gr 38C, and ten smoke rounds. This setup removes all ammo from the turret and leaves most of the hull empty, save for the rear side section which you need to be mindful of.
Angle the hull a lot at all times, but also angle the turret at roughly 45° between shots. This greatly mitigates your frontal turret weakspot, where the armour normalises.
Even in an uptier, having 6 crew and tons of empty space means you can survive quite a bit.
Remember that the Pz.Gr 43 has enough explosive filler to guarantee overpressure, the TS does not. So reserve the TS for sniping or for very hard targets, and use the Pz.Gr 43 on everything else. Considering that the Pz.Gr 43 is capable of frontally penning even stuff like T-80UK, you’ll be fine with it most of the time, while the TS is the more specialised round.
Use your coax 75mm like your life depends on it. More often than not, it does.
You can use it to track an enemy rushing you. You can use it to barrel them very reliably. You can blind them with smoke. You can use the HEAT to decimate BMPs and such, and sometimes it will even kill turret crew members on IS-3s and T-54s. It also kills helicopters.
You can also use the coax to bait people out of cover if they believe you’ve fired the main gun and are now reloading.
Prioritise maps where you can engage from the get go and can force frontal engagements, like Berlin.
Trolly reverse gear is your best weapon against inexperienced CAS pilots.
Quite frankly, WT is not made for that. Realism would make Tiger IIs barely mobile, make early T-34s unable to reload while rotating the turret. CAS would have to evade after even one deterrent burst of AA fire. Tank crews would bail out in most circumstances after a disabling hit. The backbone of battles would be infantry and artillery, not tanks, which wouldn’t even be able to enter most of our city maps on realism grounds. The game would be unrecognisable.
Since we’re not doing that and focusing on vehicles alone, tbh… Might as well have fun. If I want to scratch the realism itch, I can play IL-2 Tank Crew. WT isn’t really for that.