In waiting for my multi entry (as I was this time last year)..request for further documents was completed , and since you mentioned G-mail , it is what I use almost exclusively. One of the "further documentation) was a trip itinerary..which I composed with google docs which has the ability to be saved in .pdf format..
In any event, prior ME visas do not make any difference, apparently ..as the same queries are always asked..and Last year's still appears on the interface .
I entered anyway under Visa Exempt and will request extension identically as I did least year ..the ME visa was delivered (by gmail) just as I was about to go to local Immigration..and since I am in Chiang Rai..opted to get the extension..and easily thereafter exited in Chiang Klong and rentereted thus initiating the actual ME visa..
The process , at least out of Canadian offices takes a considerable amount of time, and can be frustrating. Golen Rule , though is maintain composure and comply to any request officially , clearly ..and without opinion.
scanning documents requested is perhaps best option, but many tools available to convert pictures (jpegs) to the required .pdf ..followup questions , even text "letters" have to be done in .pdf format as well..
basically, anybody still working in an office environment would be familiar with such conversions.
I am one of those..last year. Just ensure you have proof of a ticket out before visa exempt expires..do the extension ..then initiate actual visa by border crossing/return bearing in mind you submit actual visa # and paper copy which was emailed upon award from Thai Embassy.
exactly my situation last fall..received my delayed evisa on the very day my (then) 45 day visa exempt expired. Entered Laos then to initiate it, and critical to have onward flight booked to satisfy departure within limits of the visa exempt period..it is totally the airline's scrutiny, admission for visa exempt went without a hitch...(Canadian PP and departure point)
If you do use Air Canada that is a definite..book an onward ticket just before expiry to satisfy departure...(online temp reservations can be found by google search for exactly that.."onward travel". Suggest you avoid online pre checkin since, at least in AC's case..they will request a visa and there is no provision to input anything like a visa exempt status ..and raises flags. However, with an onward ticket reservation and your flight locator # you should be fine..and when you arrive in Bangkok you should sail through with 30 day visa exempt but wise to have a hotel reservation to satisfy TM30 requirements...something you will find out about should you apply for an extension in country later.
It took me about 3 months to get 6 month multi entry visa since new post covid e system was established..(additional info on several issues was requested, mainly financial). I had six visas prior to that which involved just sending passport in to local Canadian center and getting it back within two weeks..As a result, flight time came and I entered under visa exempt, only to finally receive the multi entry about 3 weeks after arrival..I kept local Immigration notified, and initiated multi entry at a Laos crossing. Remember the only proof you have is the attachment sent by email when visa is finally approved and you need that each time you do your 60 day bounce, since all that appears in your passport is regular entry stamp , not full page "plate" type used in the past.
I have done 2 crossings @ Mukdahan this year (to update a multi entry visa). Although, I had brought both currencies..they seem to prefer Thai Baht..and yes, traditionally new crisp US dollar used to be preferred..in contrast to what I used in Nong Khai a few years back.