I am looking to invest in a printer for my work that can print on thick papers 200 gsm+ up to a3 size. It'll mainly be used to print graphic design related stuff. It'll mainly be used for internal work and not for resale purpose. So mostly 20-30 sheets per project(per 2 weeks). going to the printer for such small quantity is not productive
Absolutely opposite. Such a small demand of printed sheets means you have no reason to invest in your own equipment. Any digital print shop will be more than happy to have you as a customer. And because you need only one side printing, it's hard for me to imagine printshop, that could not help you with this task.
Check media you want to use. Take it with you when you are going to the printshop and discuss, is it possible that they have this media in stock all the time as usually they will like to have it in their climate before printing.
Take some sample jobs for test run. Nowdays there is 2 types of digital print used: toner (I add HP «liquid toner also in this») and inkjet. Toner images will be more contrast, but they are not so rub-resistant so usually you would like to add varnish on top. Inkjet have problems with variation of media it can be applied on, but in the same time print will look more similar to offset.
Check all the color management settings with the printshop. You must provide files in the same way everytime and printshop need to have consistent settings on their RIPs and machines. Make one or two test prints to check the results.