Thinking of building my own email marketing program...

I've been trying to get started with the usual suspects - Mailchimp, Mailerlite, Connectkit - and they aren't really what I've been dreaming of.

They either don't work at all, accuse me of spamming before I've even sent a single email (lol), or have an unusable user interface clogged up with stuff I don't want while hiding the stuff I actually do.

I'm thinking of getting someone on Upwork to build one for me with minimal-but-customized features and park it on my company dashboard page.

I have minimal needs, just gather a bunch of sign-in contacts and auto-send them the odd greetings and updates. Also a sales sequence for prospects, and maybe some internal company info for my team.

Anyone have thoughts about going this route? Is it doable? Are there pitfalls I'm unaware of?

What would I need to ask for to get it properly built?

(I'm on the business side btw, not the programming side.)