That works - most any itinerary that omits Islay will be simplified. It is a GREAT place to visit but the logistics do complicate a bit. However -- The primary reason (not the 'only' but definitely the biggest reason) most people visit Islay is for the single malts -- removing it one would think they'd substitute Speyside or some other major whisky region.

Since you haven't done that, it seems distilleries aren't a major focus - right? If so, then I'd also play around a bit with the earlier plan leaving out Islay and adding that time to the Loch Lomond/Trossachs area. (If you do want to visit one, there are distilleries in Tobermory, Oban and elsewhere -- one distillery tour is pretty much like every other distillery tour. You can taste a huge range of whiskies most anywhere)

Something like:

Glasgow- 2 nights
Rent car and go to either Inverary or Oban- 2 nights
Tobermory- 3 nights
Callander area 2 or 3 nights (Stirling Castle/Loch Lomond/Killin/Doune Castle, lochs, waterfalls, etc and Inchmahome Priory if it has reopened by then)
Brodick- 3 nights
Ayrshire 1 or 2 nights
Melrose- 3 nights
Edinburgh- 4 nights
Total- 22 nights

If you do shift to the Trossachs area these two hotels are terrific:

https://www.romancamphotel.co.uk

https://karmagroup.com/find-destinat...e-of-menteith/

On any of your plans -- when in Argyll try to fit in Crarae Gardens. it is about 10 miles straight down the loch from Inveraray.
https://www.nts.org.uk/visit/places/crarae-garden