I need to configure SMTP send only accounts

The Problem

I manage multiple email accounts (personal, professional, work, university, etc.) and automatically forward all those emails to my main Gmail account. I’ve configured SMTP for each account so I can send and reply to emails as if I were using the original account. However, I hate Gmail’s interface, so I’ve been looking for an email client app for both my computer and phone, other than Thunderbird, which I find unattractive.

I came across Mailspring and liked its appearance, so I downloaded and set it up. Unfortunately, I quickly discovered that Mailspring doesn’t support “send only” accounts. Configuring it for both incoming and outgoing emails would require me to reconfigure all my accounts and lose the backup functionality I have with Gmail.

I don’t understand why the option to configure only SMTP accounts is blocked, especially since the functionality is clearly there. Unfortunately, I stopped using Mailspring within 15 minutes due to this limitation.

Proposed Solution

Allow users to configure IMAP or SMTP, according to their needs (I read a lot of people asking to use just IMAP, and I don’t see why would you block that feature too)

Alternative Solutions

Using another client…

Context

Thunderbird has this feature (which is not even a feature, they’re two separate protocols that can be configured independently)