my home's central air is blowing weak and tepid

I've done all I know to do and I could use some help.

I've got a central air conditioner for my home in Minnesota (85 and humid daily right now) and while I've got my thermostat set to 74, lately the temps in the house have been getting up to 76/77 degrees (first time I've seen that since buying the house 7 years ago).

It's an older unit, but it uses R-410A so it's not that old.

I replaced the filter with a MERC-8 a couple of weeks ago (yes, it's facing the correct direction for airflow). I tried pulling the filter and got the same results anyway, so it's back in.

The outdoor unit is not blocked or choked. I removed the top and gently hosed off the interior just for good measure.

I noticed condensation on an insulated line near the furnace/blower on the inside of the house, and ice on the insulated line on the outside of the house, so my next suspicion is ice buildup inside. I ran the fan for several hours with the AC set to "off" to melt the ice, then access the evaporator coils to spray with foaming/self-rinsing cleaner, but it looks pretty clean already.

I stuck my phone into the a-frame evaporator and took a pic downward into the blower area of the high efficiency furnace right beneath the evaporator. That's the 2nd pic up top. Does this look dirty enough to anyone to warrant vacuuming? Or do I need to move on to "coolant leak" and call a professional?