All I can suggest is you Try a newer release on your hardware (ie. live mode by selecting Try) and find out.
This TRY mode allows you to see how it operates on your existing hardware. Whilst performance will not be identical (it’ll be slower as the uninstalled image is squashed and thus needs to be expanded before it can be run; something that is done at install time) it lets us detect what issues can occur somewhat easily.
That release is EOL in regards Lubuntu, and thus we do NOT provide support for it, and any questions relating to that release will get closed. You can refer to the Start Here page for a list of supported systems for this Support and Help section of Ubuntu Discourse (just expand the Before asking a question)
To get details on release-upgrade process, look up our manual
https://manual.lubuntu.me/lts/D/upgrading.html
That link shows the 24.04 manual page (for now; will remain so a few more months) and contains details.
I will also state that I’ll consider what kernel stack you’re using now; ie. if using the HWE stack currently which it appears you are, your upgraded system will also use the newer kernel; which currently is 6.17 for 24.04(.4), but will soon change to 7.0. For some older hardware I’ve had a better experience with the older stack option, which is 6.8 for 24.04; ie. what you’re using now in fact. What will determine this is not CPU, but the whole machine especially graphics.
The release-upgrade process works on packages; if your system includes the GA kernel stack - you’ll have that upgraded for the new release; thus HWE kernel now will upgrade to the ~two year newer kernel for release you’re upgrading to. I thus often ensure I have both GA & HWE kernel stacks installed before I release-upgrade, so I have them both available on newer release.
Lubuntu had released ISOs using the 6.8, 6.11, and 6.17 currently; for live testing I’d try and find a 24.04 ISO with the 6.8 kernel which is the kernel you’re using now (ie. same hardware interaction you’ve got now, just newer software or everything else), as the one easily downloaded from Index of /lubuntu will contain the 6.17 kernel as it’s the latest ISO we’re released for 24.04 (or noble)