Going back to Sony from 4/3-lens questions

I am either addicted to the idea I need more resolution or just plain addicted to buying gear! I gave up my Sony stuff to go micro 4/3, thinking the OM1 high rez mode is all I need for the few times I actually need to print big. But Sony seems to be whispering in my ear "it is better to have it and not need it then to need it and not have it"!

Seriously, I will be shooting more events and have more of an opportunity to display large prints, plus some new lenses and the A7r5 (and the a7C) have convinced me to go back to Sony full frame.

I generally like to use two bodies with a 24-105 on my main camera and a 16-35 on the secondary camera. I was never crazy about the 16-35 G lens, but the newer PZ 16-35 seems to be a better lens and perfect for the a7c. I had been using the Olympus 12-100 on the OM1, so the 24-105 on the a7r5 will not really add much to size and weight. When the a7c camera came out I was never excited about it, I thought about using a a6XXX camera as a second body instead. The smaller PZ 16-35 made me rethink that choice.

A few of the a7r5 improvements over the a7r4 plus Tamron adding a couple of lenses I really like, clinched my decision to go back to Sony. The smaller raw file option is actually a big deal to me because for the vast majority of my shots I do not need a lot of resolution. The improved ibis should improve the performance of the Tamron 50-400 lens. I really enjoy the perspective of a long zoom. The range of the Tamron 50-400 will make this lens very usable for me. The Tamron 35-150 seems to be a great lens for shooting my granddaughters basketball games and church events. I may even start doing some portraits with this lens.

I am 74 and have been taking photos for many years. I am mainly doing travel photography. I always think I need a few primes, yet when I buy them I never use them when I travel. 4.0 and ibis always work well enough for me. I am thinking of buying a 14mm prime for shooting inside places like churches and even for landscapes as that extra 2mm on the wide end does make a difference. I am debating between the Samyang 14mm 2.8 and Sony GM 1.8 14mm. There is a huge price difference, is there a huge quality difference? I know the Samyang is manual and I think the newer version is optically the same as the older version. Just curious if any of you were conflicted over which to choose, and what did you choose and why?

I noticed the Tamron 35-150 was selling for $2,100 on Amazon and for $1,899 on B&H. I think $1,899 is the normal price, not a sale price. I am guessing Amazon is taking advantage of the fact it is not in stock at Adorama or B&H. I also think the normal price for the Tamron 50-400 is $1,299. I saw this listed somewhere as part of the black Friday sale, but I do not believe that is the sale price. Please correct me if I am wrong.

Gary