Ask M. Saylor how he did it for Microstrategy 😂😂
I did the same, like you, but back in 2016-2017, with some of my clients. I was working like a freelancer in IT consulting and I wanted my clients to pay me in BTC directly. But none of them accept BTC in their business. So I went on convincing them to start buying BTC as company funds reserve, for long term. And from that fund, they could pay my invoices.
Some they start doing this as a fun experiment, with small amounts and increasing over time. Some they didn't want it and I didn't insist anymore (HFSP). But those that listened my advice, later they were very grateful to me. And I also start giving them free BTC classes and support, how to use it, how to store it, secure it, multisig for directors, finance dep etc. Some of these companies I know for a fact they accumulated even way before M.Saylor a very good amount of BTC and they still keep it as funds reserves.
And from 2018 they start paying me in BTC. No more fiat. So I will 100% agree with your proposal to convince them to buy BTC as company reserves. It worth it.
Here you have also a very interesting case by somebody explaining step by step how to buy BTC with loans. Maybe can inspire you more.