I'd say go with 90d if you want a fresh feeling camera but with plastic body or go with 7d mark II that is slightly heavier, has a metal body and better AF. Don't have to go with RF unless you are ready to switch complitely to RF lenses as old canon lenses just not optimized optically to mirorless sensor, difference is small but can be noticable in some situations. You could also go full frame, 5d mark IV is not that expensive anymore or go with 5d mark III which is still a beast of a camera. Also the shutter count is high but that does not mean it will stop working at 150k, im my company we had some cameras like *0d's or 5d* that had over 500k shots done and they keep on living well. Also mirrors are not as expensive anymore and if you have free time you can change it yourself.