What accounting software you can use on the Amiga depends on 2 big factors. Your local trading laws, and what Amiga you want to use.
Typically, most people doing this are very small businesses to medium businesses doing their own accounts. So even a very simple package like Easy Ledger might fit the bill. If you do your own, you certainly can use an Amiga for basic accounting. Accountants aren't allowed to anymore.
https://www.mcguirewoods.com/Client-Resources/Alerts/2015/2/New-EU-Accounting-Directive.aspxIf you are SELLING accountancy services, for use in the EU, it just won't do what is needed to comply with the new EU accountancy regulations.
Why is complex, but it boils down to this with Amiga releases and EU history;- Prior to 1993, nothing had to be compliant with an EU standard, but might require local rubber stamping as "suitable for use" when selling accounting services. Most packages didn't really take import/export affairs into consideration as well as you would need now, but were OK, if you can stand the look of the thing. Some of it was written in Hisoft Basic or even AMOS, the PD versions (freeware, not open source usually). Even that could do your job, if you look, and check it will run on your local Amiga.
If you are doing your own accounts, it doesn't matter. If you are using accountancy services, THEY have to comply and are hiking their prices.
In my neighbourhood, UK, All PLCs have to be independently audited, they pay the bill, but don't have to use EU compliant accounting software so long as they can present legitimate records to the auditor (who must use EU complaint methods to assess it and either pass or fail the set of accounts). Sole traders do their own accounts, don't get audited very often, and wave two fingers at the EU and everybody else except their local tax service. Who don't have to talk to anyone except the local ruling class.
What does matter if you are a sole trader is submitting tax returns, and I'd better get mine sorted quickly, I'm 4 years late already. Got another 16 years before I'm as bad as Donald Trump with things like that.