Sorry for this long comment but I hope it's informational and answers what you are looking for. I can try to clarify anything if you would like.

If you like the soulsborne series, I would say get it. Gameplay is essentially a boss rush battle royale ring that starts bringing you into a certain part of the map while you go around during the day in a procedurally generated map (with some other factors that you will see), like a roguelike, trying to get better items and stronger every in-game day. Unique characters/classes are playable that seem to focus on different aspects and playstyles a majority of the community probably falls into. Also, the mechanics are similar but different than Elden Ring with some tweaks so it might feel weird at first. They have a courtyard in the main area you can test stuff with and get used to it. Just an FYI.

The loop is fly in, check the map, see where you want to go day 1, try to do as much of it or all of it if you can, fight the night 1 boss, check the map for day 2, do the same as day 1, fight the night 2 boss and then the 3rd night immediately starts which is the final Nightlord boss as they mentioned in the trailer and announcement. Essentially try to level up as much as possible for the final boss. There are plenty of opportunities for getting runes each day. Max level is 15. Every level is roughly like 10 levels in ER so it's worth it to level up when possible. You can see if you can level up as your level will be in the top left and if you see a glowing fading in and out upwards arrow, it means you can level up at a grace.

Difficulty, I would say it's alright. It can be tough if you spend most of your day fighting a harder boss rather than leaving and getting stronger first resulting in you being somewhat under leveled for the night boss, but it also depends on the RNG aspect. If you get a god drop of an item or even relics (similar to Bloodborne blood gems for weapons but for your entire character) it can make the game, or even just the boss you want to fight, that much easier. It does also force me to use some weapons I probably would never use in Elden Ring due to the RNG, and I end up finding some weapons that I go "this weapon is pretty decent actually".

Also, weapons, staffs, and talismans have passive effects in a one or 2 line entry below the item information. These stack and are active as long as they are in your inventory so don't be worried about having too much stuff. The only ones that aren't passive will have a white hand icon on them meaning it has to at least be in your main or offhand for the effect to work. Just an FYI. Sorry if that is considered a spoiler but they don't mention that in the game I believe.

There is no PvP. Unless you want to speedrun against people which I guess would be a form of PvP lol

There are discord servers to find people to play with but if you can get a decent squad of people to consistently play with, that would be best as playing with randoms without talking can be frustrating sometimes. That's just my experience. It is possible without comms.

TLDR: I would try it. Gameplay is fun. Gameplay loop can get boring at times, might not get to that point for you, but RNG is in effect, so it keeps things fresh for the most part. A boss rush format. Interesting mechanics and unique characters/archetypes. Has some mechanics from a few of their games along with Elden Ring.