You want to do focused work.
Quality over quantity.
Sounds like you have been doing alot of work over the past year, however, not seeing much change.
Taking a new look at how you are addressing things will help. Consistency with 10:00- 15:00 per day is key.

Stretching and mobility are 2 different things.
From the FAQ
“Stretching only focuses on lengthening short and tight muscles.
Mobilization, on the other hand, is a movement-based integrated
full-body approach that addresses all the elements that limit movement
and performance including short and tight muscles, soft tissue
restriction, joint capsule restriction, motor control problems, joint
range of motion dysfunction, and neural dynamic issues. In short,
mobilization is a tool to globally address movement and performance
problems.”

Yes, a mobility session is limited to 3 mobs.
This is a solid amount of work without doing too much in 1 session.

In Becoming A Supple Leopard there are some sample mobility programs within Part 4 Mobility Prescriptions. There a couple ways to use this section as explained on page 442.
These are to help the reader learn to create their own mobility programming.
Becoming A Supple Leopard includes a 14 Day Whole Body Mobility Overhaul om page 470-471.
This can be used to create your own customized program or follow one of the sample 14 day mobility programs page 472.The sample programs are samples. Use to build your knowledge and ability to apply that knowledge to create personalized programs to address what you need to address.
As noted there is no one size fits all mobility program.

Another option is 14-Day Mobility Challenge | 7 Green Lights | Day 1 found within the Episode tab.
You’ll address different areas for 1-2 days at a time.

Working on your entire body takes time and is a large task.
Too much to address each day.
Start chipping away at it.

You can continue weight training and playing football as you begin to work in mobility time.

I recommend beginning with one of the sample programs in Becoming A Supple Leopard, or the 14 day Mobility Challenge. As you are working on an area you may see other areas start to improve as a result of other things in a better place/positioning.