I don't play comp so idk how useful my advice is but I say the weapon mainly focuses on holding down space and finishing off anyone who's weak.
It can push forward well, especially with its range but one of its biggest weaknesses is getting rushed down so I try not to over extend and put myself in a spot where I end up fighting two or three players by myself.
Machine obviously does well with ledges, I find it more consistent hitting people over ledge with Machine than regular Slosher so maps with a lot of verticality help it a lot in catching people off guard or simply making the enemy team back off.
You could also try to distract the enemy team by sloshing in a spot that they need to push in but I only do that to delay their push, not to actually get a kill unless an opportunity shows up.
Overall, I see vanilla Machine as the kit that focuses on holding down space with all its chip damage from the main weapon itself and fizzy and then finishing anyone off whos weak from a fight or is currently in a fight.
Booyah bomb also helps with that playstyle by keeping it alive, forcing the enemy team away from an area, and painting more of the map.
You could also try fizzy spam with LDE but I don't play the weapon like that so I can't say much about it but Fizzy still helps it a lot with movement, combos, contesting/holding an area, and painting for special.
Personally, I use two subs of scu since 220p Booyah Bomb is really expensive and I think Machine can afford at least two subs on it.
For Machine Neo I would say it has to push ahead more than vMachine since it doesn't have Fizzy but it's range is good enough where that's not too much of a problem.
It's AoE damage is still very important for comboing with other weapons and point sensor gives it more information that makes it easier to catch anyone trying to chase it down.
In a coordinated team that might not matter that much but it's still good for hitting over ledges since you'll know exactly where the player above you is moving while you're sloshing at them.
Machine Neo also doesn't have to worry about an expensive fizzy so LDE isn't as important on it, you could run something like Comeback or anything else really but you should still have one sub of ink saver main for the extra slosh when Comeback isn't active.
I also throw out point sensor usually right before using Zooka if I don't currently see anyone around but it's still Zooka so you can pop it randomly and probably get some value out of it lol
Besides that, I would say the 2nd kit is slightly more aggressive but still plays as a midline weapon that focuses on chip damage and securing kills, main difference being now that you'll get into more fights and you have a Zooka that can immediately get quick kills, either from high ground or from anyone getting too close to you
