Monetizing a small SAAS side-project

Hi there fellow IT freelancers. I have a SRL and currently do consulting work. I developed a small side-project that I want to try monetizing.

I was wondering if any of you did anything of the sort; and if you have a service to recommend to simplify all the invoicing/reporting? The ones I looked at so far are either very corporate; or very US-centric (LemonSqueezy; Stripe) - I'm not sure how straightforward it really is regarding Belgian reporting?

If you did/are doing something in this vein I'm happy to pay for one hour of your time to learn about your experience/setup ;-)