After all G.I benefits are used what type of funding is available to get continue on to get a master’s degree?

In addition to the steps LTC Eugene Chu mentioned (especially joining the National Guard*), check with your state's Veterans Affairs Office to see if there are state programs/scholarships available for veterans residing in that state.

There are many resources to find scholarships for veterans*, you just need to do some creative internet searching.

If you have a disability rating of 10% or more from the VA, you might be eligible for VR&E if a Vocational Rehabilitation Counselor determines you need it.
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* Many states will fully fund a bachelor or graduate degree at a state university if you belong to the state's National Guard.
* https://www.bestcolleges.com/resources/military-veteran-scholarships/
* https://www.dvs.virginia.gov/wp-content/uploads/2021/01/Veteran-Scholarships-and-Grants-1-19-21.pdf

Partial GI Bill helped me to obtain MBA. A few thoughts...

1. Look for outside scholarships along with GI Bill
2. Look at accelerated graduate degree programs
3. Rejoin military in ARNG and see if state will cover tuition at a public university

Veteran Readiness and Employment (Chapter 31), formerly Vocational Rehabilitation maybe:
https://www.va.gov/careers-employment/vocational-rehabilitation/