In case it helps anyone: my Specialized Sequoia came with an FSA chainset that's 48/32T and works with a standard 105 front derailleur. The cassette is an 11–36T Sunrace and also works with a 105 derailleur (GS cage but no extender as far as I am aware). So it's possible to make a non-GRX Shimano road setup work. Though I don't know if I would have necessarily gone for this exact setup had it not come with the bike.
Pictured with 1.9" 650B Gravel Kings (probably the largest tyre that the chainstays will clear).
In case it helps anyone: my Specialized Sequoia came with an FSA chainset that's 48/32T and works with a standard 105 front derailleur. The cassette is an 11–36T Sunrace and also works with a 105 derailleur (GS cage but no extender as far as I am aware). So it's possible to make a non-GRX Shimano road setup work. Though I don't know if I would have necessarily gone for this exact setup had it not come with the bike.
Pictured with 1.9" 650B Gravel Kings (probably the largest tyre that the chainstays will clear).