L14-30 inlet to L14-30R box

I currently have a Generac transfer switch (Generac 30-Amp Indoor Generator Safety Transfer Switch Kit for 6-10 Circuits | The Home Depot Canada) wired to a cable with a L14-30P plug that I use to plug into my Anker F3800 batter generator inside in the basement. This works great until the battery runs down and we have no solar to charge it backup and solar in the winter won't be a great option here (someday I plan on putting a few panels up and taking advantage of the two XT60 solar charge ports on the Anker).

We just recently purchased this generator GXS7100iRD - 7100 Watt Dual Fuel With Remote Start Inverter Generator and now I'm trying to figure out the best way to set this up with my existing battery setup.

With that all that said would something like this Reliance Controls 30 Amp Power Inlet Box | The Home Depot Canada on the outside of the house for the gas generator to a L14-30R receptible box on the inside near the F3800 and Transfer Switch be an ok solution? In my head I could simply take my cord and unplug it from the Anker F3800 and into the receptacle box when I wanted to supply Gas generator power to the transfer switch?

Sometime down the road I will want to invest in a EG4 Chargeverter and use that to supply power to the solar inputs on the Anker F3800 .

I'm going to hire an electrician but looking for confirmation that what I have in my head could be done before reaching out to one. Looking for any advice on other solutions or concerns you experts might have