Will Microsoft ever provide a viable email client again?

I'm a long time user of Outlook - from long before it became Classic. It was a perfectly viable email client - not perfect but useable.

I tried New Outlook when it was first promoted, and quickly switched back because it was functional deficient at the time.

Since then, Microsoft have introduced issues into Classic Outlook - specifically:

• It can't maintain a set Office theme. I can set a theme (the Microsoft default system setting) but it corrupts and highlights in black (for example) after a short while. (I believe after the PC switches off the screen or the PC sleeps)
• It 'corrupts' while composing longer emails meaning that I cannot send or save the draft but must start again from scratch.

I tried new Outlook again - it's not as bad as it was - but:

• It still doesn't allow me to present my email accounts in the order that I want to see them.
• It doesn't manage Contacts and Contact Lists correctly - while Classic Outlook does.

So I now have my PC set-up to use both Classic and New Outlook and have to switch between them depending on what I need to do ... 🤷‍♂️😠

My requirements aren't trivial, but they are not that complicated:

• I need to manage multiple email accounts - around 10 in all. I want to be able to present them in my 'most used' order - i.e. I want the ability to sort the order of accounts.
• I have a Microsoft account that I use to log-in to my PC etc.
• My default email account is Gmail
• My default calendar account is Microsoft
• I want a single default set of Contacts and Contacts lists that I can use in conjunction with any of my ten email accounts
• I want my email client to be stable

Is that too much to ask? And why, oh why, can't Microsoft deliver such a solution?