Larger pipe size (2.5" or 3") to standard 2" inlets (Filters, Heaters and Return inlets).

[6 ft under]

Pool owner here trying to understand piping and flow efficiency for a DYI upgrade project:

Background:
1950's in-ground pool, cement base fiberglass walls. 20x40 average 6' deep. 36,000 gallons.
1 main drain with 1.5" black line surfacing at the east skimmer.
2 skimmers across from each other, center of pool.
2 return inlet jets opposite sides of each other, opposite ends of the pool.

Goal:
efficiency, upgrading, comfort and beauty.
Maximum performance at 98% turnover would put it at 100 gpm.
Desired flow rates with a 2.5" pipe is 95 gpm and 3" is 119 gpm.
Very rough calculation of TDH is 60 based on 1.5" main and 2.5" every where else.
Planning to upgrade new skimmers and add two additional return jets, totaling 4.

Considering max efficiencies of a 2.5" hard PVC pipe at 90 gpm at 6 fps and 3" at 138 gpm, the math tells me I should run 3" pipe!
feels like over kill to me.

So, dialing it back to find a sweet spot, I come up with this:
Desired flow rate of 82.5 gpm using 2.5" pipe at 95% turnover rate (3X a day).
*NOT MUCH WIGGLE ROOM at 82.5 gpm with 2.5" pipe.

This is where my mind warps:
I can find VS pumps with 2.5" and 3" connections but everything else (Filters, Heaters, Skimmers and inlet jets) are no more than 2".
What is the solution to the inefficiencies of reducing pipe size to connect to the equipment?
What are the problems if I do so?
Can I use a 2.5" Hot Tub return jet as a return inlet jet to the pool?
What do I not see or understand at what I have described?
Do I have to move to more of a commercial application?

or is the solution to settle with 2" pipe and work with the max flow of 63 gpm at 6 fps, working the equation backwards?

Looking forward to the feedback..

[Teapot1]

What is your filter setup, this will have a major impact on how much water you can flow and therefore the best pipe size. The pipe size is not the biggest factor in the system.