There will be a season five finale

It's disappointing on one level, but getting a finale, an ending to season 5, is good news.

Season 6, whenever it ends up being filmed, can go forward without carrying over the unresolved plotlines of the previous season.

I give the writers their share of grief, and I think it's mostly deserved when I do. However, it's also fair to say the show has been challenged
by some of the worst luck with behind the scenes issues that I can recall. Aside from season 1, I think every year has been impacted by some shakeup or availability issue.

I'm hoping whatever they choose to do with season 6, they can effectively plan the course and execute the vision with minimal disruptions.

It's better than nothing, but don't be too surprised if it is a mash-up / dog's dinner due to the rushed production, erratic and bizarre nature of Season 5, and the general loss of focus and momentum of the show.

I'm not sure why people keep saying 22 episodes were planned. It has been 20 episodes from the beginning. That wasn't a change that was made because of Melissa's pregnancy. It has been the number for quite awhile.

Well...whatever "finale" we get, it doesn't look like we'll be getting any resolution on Lex. At least according to this interview with Jon Cryer.

https://ew.com/tv/supergirl-jon-cryer-lex-luthor-season-5-finale-fate/

I like Cryer, but its time for this Lex arc to end. Let's hope we at least get some resolution to the Leviathan arc. If not, this won't really feel like a finale, as much as it will a SUPER long mid season hiatus. I'm kinda dreading that we'll have to deal with Lex and Leviathan through season 6. That's just...too long to drag this story out.

After seeing these comments from EW,I'm now very curious what the original plan and how Lex was going to be defeated were.I'm hoping that gets revealed at some point after episode 19 airs.

As 5x19 was filmed in its entirety and 5x20 was mostly complete and now they have decided to reimahe the two as a single regular size episode, I fully expect it to be action packed. No time for blinking. As scenes are shot out of order they very well could have some plot point resolutions filmed. Although, Jon Cryer has not so subtly suggested Lex get a rewrite. Anyway, they obviously have a lot of material to work with and Ifeel hopefully optimistic.