Do you have a preferred Cloud Service Provider for MS Licensing?

We currently use a CSP (interlink) that we buy more than 600 E3's, 200 Premium Business, and 200 F3's - along with a number of other MS products such as copilot and Power BI, etc. The most savings we're seeing is 5%, if that, in many cases around 3-4% off list.

They tell me they aren't the cheapest but part of the premium we pay for is support through them. Looking at our ticket logs we opened about 4 tickets in all of 2025. If we want to add or remove licenses we have to call them up, no portal to self serve.

Not saying this CSP is bad, just looking to see if there are better opportunities else where and if so, whom do you prefer to use?