Which Microsoft tool?

Hi all, I've just bought a new laptop and I'm looking to start my own business, which will be a career pivot after a couple of decades in journalism and comms. To supplement my income, I'm considering offering freelance comms support. I'm used to environments like government, funded projects etc.

I'm deciding between Office for business (one-off payment) and 365. I don't need the features of 365 for my pivot business, although some would surely be useful.

However, I also don't know what it looks like when a freelancer works for an NGO or such like - would they ask you to log into their 365, and if so, would this work on my laptop alongside standard Microsoft apps installed for my own use? (I.e. non-subscription).

Tldr: I'm wondering whether Microsoft 365 would interfere with regular desktop apps, and if login in remotely on a computer not supplied by the company is something a company would ask a freelancer to do anyway?

I have only ever freelanced for news organisations, but I was a desk-based producer, so it was in person. The world of digital nomadism, or however my life ends up looking, is new to me!