DanOwens

If its for intonation and simply having an idea of what's going on, you could mount one of those tiny monitors to a speaker stand (I've worked with a few guys that do this). If its to 'feel' then a backbeat or similar? https://www.gear4music.com/PA-DJ-and-Lighting/Behringer-B205D-Active-150W-PA-Monitor/CEZ

Around 2017 I started singing properly; I put loads of work into technique and growing my confidence and I thought 'I can't believe I've missed out all these years'. Then COVID turned my mild asthma into COPD, and there are about 3 times EVERY day where I question whether my medicine will kick in before I pass out from suffocation. Every time I try to sing, I get about 30 seconds in and then my chest seizes up. I hate it.

I like the song but wow that's some Cher-level autotuning on the lead vocal.

My teacher (Steve Berry) taught me to use single-note drones (sometimes called cello drones) and bow long notes whilst blindfolded to improve intonation. I would play up and down a scale, and really isolate what I wanted to improve, for instance I would focus on single-position shifts and bow the notes of the G major scale against a G drone, then change position and do the same. I spent hours at uni doing this and I found it really meditative. No metronome means no timing pressure, so you focus on the pressure of shifting and fingering correctly. Once you feel confident then introduce a metronome, but now you're focussing on shifting in tune AND in time when you SHOULD have the 'in tune' bit down. I used to practice for around 4 hours a day with long, regular breaks and over the 2 years I did this, my muscle memory improved no end... then I played mostly fretted electric for 15 years and lost 70% of it, but at least I know where I'm wrong whereas I used to listen to recordings and cringe that I didn't realise (when playing) how bad I was. Now I know!