How you handle the accounting/finance part of your IH projects?

Hi there,

I am wondering when you are starting your IH projects as a side hustle or after-work projects. How do you guys handle the accounting/finance thing?

Taxation can be complicated and the taxation authorities never miss, do you do it as a sole trader or do you set up a company to handle multiple IH projects?

Which tools (Excel or others) you use to manage the P/L for individual IH project?

I am in the UK but welcome any sharing from around the world!