[RKCRLR]

I have a 2019 Shield TV Pro running Kodi 18.9.  
I'm trying to get the TV Guide to display in 1080p and 1080p content upscaled by my TV but have everything else upscaled to 4K by the Shield.  I've whitelisted 1080p and it isn't upscaled by Kodi/Shield.  However, my 720p content is also getting upscaled to 1080p.  I can manually force it to 4K when I'm watching the source.  

I set the resolution to 1080p and the refresh rate to 59.94.  I set my player settings to adjust refresh rate on start/stop.  

According to the Kodi wiki the resolution setting in display settings "Changes the resolution of the User Interface. Has no effect for playback."  And a it says non-whitelisted items "match the desktop resolution (and refresh rate)".  However, it appears that the resolution setting actually controls what resolutions non-whitelisted content will playback at.  
Is this correct?  
Does the the player refresh rate setting only match the refresh rate or does it also control the resolution?  
What is meant by "desktop resolution"?  Is it referring to the display capability or the resolution setting?  

If I change display resolution to 4K then the 720p material is upscaled to 4K.  The problem with this is my display takes a few seconds to switch resolutions and since the guide is being displayed in 4K I have to wait for the resolution change every time I start and stop a 1080 source (which is most of what I watch).  However, if I switch from to a 1080 source to a 720p source using the guide without first stopping the 1080 source then the resolution isn't changed and the 720p source is upscaled to 1080p.  This is my current workaround for the resolution switch delay.  Is it supposed to work this way?  

If I change the display refresh rate setting from on start/stop to on start only then the resolution is still stuck at 1080 when I stop a 1080 source and start a 720p source.  Is this the way it is supposed to work?  

Ultimately, I would like to use my Shield Pro to upscale everything at a 480 and above resolution to 4K using it's AI-Enhanced mode.  The AI-Enhanced mode works on 720p material when played from Kodi but doesn't work on the 480i and 1080i sources since it doesn't work for interlaced sources.  My understanding is Kodi deinterlaces everything on Android and (I've been told) there is no way to stop it.  
Is there a way to tell Kodi to only perform deinterlacing but then allow the Shield to do the upscaling so I can use the Shield AI-Enhanced mode?

[RKCRLR]

Well, I updated to Kodi 19 and my workaround for avoiding the resolution change delay stopped working.  In fact, the situation got worse.  If I bring up the guide (which stays at 1080 if I don't stop the 1080 source) and switch to a different 1080 source, I have to wait for the resolution to change to 4k and then back to 1080.  So I've had to change the interface resolution to 1080. to avoid this.  But now I have to manually switch the 480 and 720 sources to 4K.    

Is there a way to have the interface resolution set to to 1080 so I can avoid the resolution change delay when I watch 1080 sources but have 720 and 480 material automatically upscaled to 4K when played?  

Edit: Well, I got my workaround working again.  For some reason I had to remove 3840x2160 29.97Hz from the whitelist.  And now a 720p source will automatically upscale to 4K even if I don't stop playing a 1080 source first, even with the refresh rate set for on start only. 
But it would still be nice to be able to have the interface set to 1080 and have 720p content automatically upscale to 4K.