RF Mount

[Sharpshooterr]

1, I've not yet met a EVF I get on with, and maybe I'm just being precious about my photography, but there's something about them that I feel is like a barrier and keeps me out of the image too much.

2, Maybe I'm just too used to my DSLRs and it's entirely in my head.

3, But I couldn't help thinking that investing significant amounts in EF glass right now would be a waste Sony mirrorless that I've had a hankering after instead.

Pete, I'll throw in my two cents.
First so you can see where I'm coming from.
I've been using an R5 since November, all with EF L glass on the Canon adapter.
I shoot mostly portraits(fashion) and sports.
I use or used a 5Ds, 1Dx and 1Dxll.
Next I looked at your website, it looks like you're mostly a landscaper. That's where a ML will bring you the least bang for the buck. The strength of ML is in the focus system. If your subjects are distant scenes you could do just fine with Manual Focus! Most of the benefits of ML will be lost on you.
So why did I go ML? I shot a model session where a full 25% of my 500 shots where miss-focused. I had the same dilemma with sports and I use the best Canon has.
The R5 is NOT gods gift to the focus world bit I doubt any camera by any brand is except under ideal conditions but that said the R5 is VERY good. If the R3 had 45mp I'd buy it in a heartbeat.
Now onto you.....
1, Yes it's all in your head or everybody else's heads too. I'll admit, In my kind of shooting I'm usually shooting to fast to even notice anything about the EVF. But I see it exactly as the DSLR's. PLENTY of pros are using ML and it works well enough for ALL of them to not go back.
I had built the same tall walls around me as everybody else does to convince myself that ML was not needed but a tool is a tool, nothing more, it's not gonna take you to dinner. At the end of the day it's ONLY about what it spits out on paper!
Just a couple ML advantages ii that ML does away with the lensgroups. You know, worrying about can you use a 2x or 1.4 behind your slow 100-400 because it will stop focusing, that's a thing of the past with ML. also if you occasionally starts to miss-focus and you run home to micro adjust the lens/camera micro-focus adjustment. You can throw out that fancy lens focus calibration tool.
2, I'll admit, an R5 makes my 1Dx look like a toy in simplicity. The R5 is WAY more complex than any Canon DSLR ever made so there is a learning curve. From the 5D to the 1Dx they are basically the same camera. You don't even need the manual to operate a different Canon dslr. I really hope it's the same way in the ML line.
3, As has been said your EF glass will transfer over 100%. I have no plans to buy any new RF glass but eventually it will start to make a difference since it has two extra contacts with which to build in new lens features.
If I'd not had so many focus problems with the dslr's for what I shoot, I would have just stayed with dslr. 6 months ago I saw no need to change at all. Where eye auto focus can be used it will put it leaps and bounds ahead of dslr.
If what you worry about the evf, you're really worrying way to much about all the wrong things. I'm all for photographers to do what works best for them and change as the need arises, not just because there's a new kid in town. Most of us will know when that change is necessary to keep taking our art to greater heights.
SS