KDE is the natural environment for KStars, since KStars is a KDE application and uses its library and services...etc. With RPi4, KDE is usable now for the most part.

I am getting a blank screen from the latest iOS app when trying to connect to the StellarMate hotspot with the pi4 with 1.4.3 and 1.4.4

Please delete and re-install the app again. I think yesterday, there was an update that caused this and it will removed afterwards.

I tried deleting and redownloading today, but quickly got the blank screen again

OMG. It was such a stupid mistake of mine...
I was trying different options to feed RPI4.
-- 2.1A charging port of a USB hub (12V input)
-- two charging ports of the USB hub in parallel = 4.2A
-- 6A 12-5V converter
First two options were extremely unstable (RPI would just shut down after 5min-1hr).
The third option was more stable but also RPI would occasionally shut down.
It turned out that I was feeding the whole thing (RPI, hub, cameras and mount) with a 1A 12V wall wart instead of 5A power brick!
(I have four 12V battery chargers and one 12V power brick plugged to a single power strip - all have the same kind of output cable).
Once I figured this out.. All three options worked. I currently use the second.
SM 1.4.3 -all works (except for RTC) and stable
SM 1.4.4 -all works (RTC too!) and stable

I am surprised it ran anything at all from 1A.... ?

Ah good ol' layer 8 issues...

but it did! the wart was very hot though (that's how I discovered my mistake)
i guess, the system drew much more than 1A from that wart.

Yesterday, some updates became available for SM 1.4.4 (in software updater). I installed them.
After that the wifi hotspot disappeared. Couldn't restore it.
Downloaded an updated version of 1.4.4 from stellarmate.com - same story. No hotspot.
Both versions were slow to boot and showed lines about Ekos Live offline
and also red-fonted line saying "a start job is running for Samba NMB Daemon".
That message stayed there for more that 1 min (during boot).

Reverted to a week old version of 1.4.4 - hot spot is back, no Ekos Live and Samba messages.

Just reporting.

Ouch... on the second boot the Samba message is back and no hotspot...
So strange.
This version worked for me for several days.

Went back to 1.4.3 (Mate). All is well. Will wait for 1.4.5.
1.4.4 is flaky for me.
In 1.4.4 KDE UI was very sluggish. KStars/Ekos when started were OK/fast.
And the hotspot situation is still a mystery to me.
In 1.4.3 the hotspot was also doing tricks but at least I made it work...
I realize, those are beta releases...
(RPI3 is rock solid/stable).

I have this latest version, and installed all updates this morning, no issues here and GUI is a little sluggish, like when you click on any item in top left it takes a second to open the menus...Hotspot ok, so not sure why you got issues...