The same here... I own way to many RPi's =D
I was actually considering to buy the 8Gb version and let the 2Gb trickle down the priority chain and do other less prioritized stuff. But there seem to be a shortage of 8Gb RPi's now.(locally at least)
I tried looking at mem usage during playback, it doesn't seem to be a big deal... but sometimes there more to things than you can easily see 
I'll give it i try then.
Thanks.
Just around launch of RPi4 a bought 2 of them, 1 4Gb and one 2Gb. For some reason I ended up using the 4GB one for libreelec and the other one for misc Home automation tasks.
So to my question, is there any gains/benefits to use the 4Gb version for libreelec and kodi. Or can I do a switcharoo and still be sure that all my 4k hdr lossless audio movies continue to work as nicely as they have done for the last week or so..
I _know_ there are gains to be had for my other projects with more ram... but my HT comes first =D
The new case arrived yesterday, the hdmi-cable is seated much better, I haven't been able to reproduce the error again. So I'm blaming the cheap cable and old case combo.
Is it well known to have issues starting kodi if there is no hdmi cable attached?
I guess kodi does some checking/probing for resolution and such, maybe that fails and causes it not to start?
I'll try to check "resolved checkbox" at the top. If I can't, maybe some moderator can check it for me.
Again, thanks for all you help.
It's not an Argon One case is it? We see a lot of issues reported with those.
No, it's an Pibow Coupé 4 - Rainbow, but I _don't_ think it's the case's fault, I rather blame the cable, low-end from a cheap warehouse
I ordered a heatsink case that arrives in a few hours, that should rule out hdmi-connector-not-fully-seated-issues. Mayby i'll get a smaller hdmi-micro -> hdmi converter today as well... to rule out the potentially crappy cable. But i'll first see if just changing the case fixes it.
I'll most certainly follow your advice Klojum, if the problem comes back.
If I get the problems again (even after changing cables and case) , I cannot change log levels via GUI (since it won't load then), is there a way to do it via command line (ssh)?
Big thanks to all of you.
Thank you for your swift reply Klojum,
Those were the logs I found, no crash logs at the time of posting....
Sorry for just grep'ing for "ERROR", I thought that we be enough. Will do better next time 
Oddly, Now it suddenly starts and works like it should.
During the last 2 days I've must restarted it 10-15 times, both through SSH and power cycling. But it never started properly anyway... but now, just because I posted....
I have a theory: My case and my micro-hdmi cable don't seem to be fully compatible (it seems like the connector cannot get fully seated) so the connection sometimes fails.
Could it be that kodi/libreelec can't start properly if there is no screen attached during boot?
Edit:
If i need to post complete logs. should I do it in the post, or put them in pastebin?
I installed libreelec on a fresh SD card last week, only tested and configured it to run (including ssh). Played some movies as POC. And left it there to finish other HT-projects.
Now I cant get Kodi (i guess) to start.
LibreElec starts to boot , the screen is black but with LibreElec(official): 10.0.0 at the top left corner.
I did set up SSH and I can access it.
Not sure exactly what logs to look in, but this is all ERROR's from kodi.log if thats any help:
2021-09-13 12:10:32.081 T:777 ERROR <general>: DBus error: org.freedesktop.DBus.Error.ServiceUnknown - The name org.freedesktop.UPower was not provided by any .service files
2021-09-13 12:10:32.131 T:783 ERROR <general>: CAESinkALSA::Initialize - failed to initialize device "hdmi:CARD=vc4hdmi0,DEV=0"
2021-09-13 12:10:32.258 T:777 ERROR <general>: CWinSystemGbm::InitWindowSystem - failed to initialize Atomic DRM
2021-09-13 12:10:32.261 T:777 ERROR <general>: CWinSystemGbm::InitWindowSystem - failed to initialize Legacy DRM
2021-09-13 12:10:32.457 T:783 ERROR <general>: Sink Timer expired for more than buffer time: 300l
2021-09-13 12:10:33.421 T:783 ERROR <general>: Sink Timer expired for more than buffer time: 300l
2021-09-13 12:10:34.008 T:783 ERROR <general>: Sink Timer expired for more than buffer time: 300l
2021-09-13 12:10:34.325 T:777 ERROR <general>: JSONRPC Server: Failed to create serversocket(s)I'm running an RPI 4G, and used the official installation.