I have a domain registered on G Suite and I'm building a app that needs to send Transactional email such as password recovery and email verifies. The smtp for gmail has a low quota for that. I need to build a server running postfix to send e-mails SPF registered for gmail so I can bypass that limit. Yes I have seen services like mailgun but i need to build one because of cost. I'm totally new to email serving so could any one give me at least some tips on how could I achieve that? keeping my domain on google but sending email form a specific account from my postfix debian server. Also, I'm using Google cloud.
Any help would be highly appreciated.