1997 Volvo S90 Mixing Oil/Coolant

Hey all, I have the car mentioned above and its been a rollercoaster with this one. I have had this car since October 2019 and when I bought it it had 222K miles on it. It was leaking coolant from the beginning but there was no internal head gasket leak. It was leaking in the rear driver side of the engine on the outside of the block. One day I was driving home from work and I let the coolant leak to absolutely nothing. It blew the headgasket with an internal leak, warping the block and head, mixing coolant and letting coolant reach the combustion chamber. I used Bar's Leaks HG-1 headgasket sealer and after an oil change it fixed my problem temporarily, for about a few months.
I wound up rebuilding the motor with the same head/block, replacing the headgasket, getting the head resurfaced and cleaned. The timing belt, spark plugs, radiator hoses, camshaft seals, crankshaft and camshaft control modules were replaced. Recently I fired up the car and it had the coolant light on again. I topped it off and it hasn't come back on for a few days.
This evening I had a Check Engine light come on for a rich fuel mixture in Bank 1 (P0172). The dipstick is milky again after using more headgasket sealer. I figured since the block wasn't resurfaced and likely still warped, it was bad enough that there is some coolant-oil mixing. There is zero smoke coming from the dipstick now so I don't think the coolant is reaching the combustion chamber.
So milky coolant and a rich air-fuel mixture. If the headgasket leak isn't allowing coolant to go to the combustion chamber, what sealer would work where it doesn't harden from touching the exhaust gasses? I'm not sure if the temps of the oil would be enough to create that barrier to seal it off. Maybe the two things aren't related but I'm inclined to think they are. The car runs smooth, and as you can see from the pictures the cross-hatching is still somehow almost perfect at 232k miles.

Any tips or people with experience here would be much appreciated.