I'd love to hear someone else's strategy here. I feel like I am not doing the best I can with rental cars/loyalty points.

I primarily fly on American Airlines. I am putting this post here because I am going to ask about different rental cars, etc, but the only consistent thing or change I'd make is if I should be using one to get more AA miles and Loyalty Points. There's no general Rental Car channel at least that I could find.

I have the Chase Sapphire Reserve but no other premium cards right now.
I have historically rented with National - I love the Exec Status with CSR and getting to pick whatever car I want.
I almost always rent from an Airport and almost never for more than a week.
I do like to use Costco Travel which gives great rates on Avis and Alamo, so I have rented from them too.
Avis is much easier for me than Alamo in that it required no print outs or standing in line, etc, just like National. But I didn't get to choose my car. I don't overly care about that, but if it's close, it is fun to choose. I did see that I could make a selection somehow online, but maybe I missed the window for that on Avis. An Advantage for Avis is that it is in CSR portal AND Costco.
The CSR Portal gives 10% back on rental cars and has National, Alamo, Enterprise, Avis, Hertz, etc (all the contenders) available to reserve through the portal. So I also like to reserve through there, depending on price.
I am Marriott Lifetime Titanium but have Hilton Diamond through next year and have a couple IHG cards. But 99% of the time I'm staying at Marriott, only if I can redeem points or am in a spot with no Marriotts do I go there. But maybe there is a partnership there?

I recently reserved an Avis car and for a two day rental, I got 1,250 AA miles. For the National Car ones I seem to get 1 Rental Credit every time and I need 6 Rental credits to then get 1 free rental day. The AA miles through Avis seem to be much better? That rental was through Costco Travel but my preference on AVIS.com was set to AA miles.

I have 7 figures worth of AA miles, so it isn't about "needing" anything there, but it just seems better than the rental days which take so much time to get.

So, given this information, is anyone doing something I should consider? I'd be open to switching rental car companies or getting a new credit card if needed. I don't think the CSR/Avis relationship gives me a higher tier status like CSR/National does.
Has anyone selected AA as their reward partner on National? I couldn't find what they earned. And on Avis, I don't know if it earns 625 a day or if every rental is 1250 or how they determine that. I couldn't find charts surprisingly but searched multiple terms. I also like convenience of just having one company to work with where all the reservations, etc are all in the same place. But, I like points and $ more than that lol.

I'd love to know what anyone thinks and to use your strategies to be better in this space.