I’m not sure I understand the “side business”. You already have a business. You’ll likely get a 1099 for the grant. Any other income can be reported as sole proprietor income alongside that. You can deduct any appropriate expenses used for business.
You may want to clearly establish that the equipment was purchased for business and not a hobby. https://www.irs.gov/newsroom/heres-how-to-tell-the-difference-between-a-hobby-and-a-business-for-tax-purposes
If “expectations are clear” and they are not meeting them, then talk with them.
If “expectations are clear” and they are meeting those then not sure I understand why the problem is with them. Phones are allowed, expectations are met. If you are concerned about “low effort” then make it clear that the appearance of giving effort is a priority for you, regardless of outcomes.
Relay is one of the worst banks I’ve ever used. Complete mess, website is riddled with bugs, no customer support. So happy we left.
You should be able to reverse ACH transactions you did not initiate within 3-5 business days.
Grants generally aren’t special income, its just regular taxable 1099 income. There are no special grant taxes.
https://www.irs.gov/charities-non-profits/private-foundations/grants-to-individuals