Lvi, Kyiv, and Odesa are all worth visiting. Lviv in particular is known for great restaurants and a historic downtown. Though food is consistently good everywhere in Ukraine. I have business and personal reasons to be in Ukraine, so I haven't really done much tourist stuff myself. But that stuff is operating too. Odesa in summer, for example, is a busy beach vacation destination – the first year it was empty because the beaches were full of landmines to prevent an invasion. But they've removed them all since.
There's not _that_ much to say re: practicalities. Pretty much everything works fairly normally. And at this stage of the war there's no longer checkpoints everywhere – they've successfully found most of Russia's infiltrators. In theory you're under martial law. But cops are chill so long as you're not doing anything stupid (e.g. don't take photos of sensitive things, follow curfew, don't post videos of anti-aircraft activity or recent hits (helps Russian targeting) etc).
You have curfew at midnight so everything ends early (curfew ends earlier in some places closer to frontlines that I've never been). You'll probably experience air raids, especially in Kyiv and Odesa. But honestly, they're ignored by most people because they're too frequent and last too long to be worth doing anything about. In a place like Kyiv, it probably averages to something like one or two people a day getting murdered by Russian air raids (31 at once a week ago when Russia used missiles to destroy an apartment building). If you're in certain big public places like big malls they'll kick everyone out and tell you to go to shelters – the government doesn't want mass casualties and easy targets. But smaller businesses don't care.
This is a good site to understand what situation is for wherever you plan on visiting:
If you visit somewhere closer to front lines it's another matter... In parts of Kherson, for example, you may literally be hunted down by Russian FPV drones. Russians use Ukrainian civilians to train new drone operators. And they even brag about it, frequently publishing videos of these murders. For example, this attack on civilian firefighters posted the other day:
https://nostr.download/17ac83681bbeebcc9ad5efaecb40f8551223c223b87dd28d9d9b7994262f9873.mp4
Finally, since flights aren't operating actually getting into Ukraine is a pain right now. Easiest is to book bus tickets, or if you have your own car, drive in.
I have medical insurance from a company that explicitly gives war journalists as an example of travel that would be covered (!). I've never had reason to use them. But you might want to check that.