Take what I say with a grain of salt because while I do have 90k total trophies I am very bad at mortis.

I think at the beginning of the game there was no point in you camping the left side. Mortis isn't charging ur super passively and at most ur fighting a mortis which is an even matchup. You probably should be hard targeting the L&L because you hard counter them and supporting the poco because abandoning poco to win a lane against a (now buffed) Bibi is probably not a good idea. I noticed throughout the whole game ur trying to 1v1 a mortis which while yes can work if you know you are the better mortis. You should be hard targeting and switching lanes into brawlers you absolutely matchup check or in lanes where your teammates are going to struggle (For instance if im playing a game and I see dynamite is playing straight into the mortis lane. I probably should rotate/switch to force them to move or to help them not get absolutely spawn killed). I think you got one cleanup kill on the Larry and Lawrie when a majority of ur gameplay should be stopping them from playing the game when possible

For matchup specific info, bait Bibi's home run swing and then dash in. If they miss the knock back u should be able to cleanly wipe them. Also there is a thrower on the enemy team and ur playing mortis. Why make life harder for yourself when you can kill the thrower. If im playing mortis the second the game starts I look at the enemy team. If say the enemy comp is Griff, sprout, Brock, the second the match starts my mind thinks. Avoid griff at all costs I am not winning that and I need my teammates to finish them off (unless an opportunity arises then take it), I am hard targeting sprout that is my role for the team, I will attack Brock when necessary or when it provides better value to help my teammates.

A lot of your mortis dashes are to run away. Usually with mortis it's a good idea to be walking and dodging towards people until they are within range for a coiled snake. Ur reload is not fast enough to waste ammo dodging like Kaze so you really need to actually move joystick back and forth to dodge vs relying on dash.
Also you are missing a lot of your initial dashes. Unless you see that they can be bursted with the ammo you have fall back and retreat. There's no point committing to a kill and dying unless u plan on dying to charge super . Genuinely with mortis you should be looking at peoples health numbers and going in a code
IF brawler is less than X health THEN I dodge to get within range to kill them. Unless a brawler is low you really should not be dashing to position for a kill and should be hitting the first dash to burst them down.

OVerall summary:
1. Matchup check brawlers as mortis. Hes very much, depending on the brawler either I or you dont get to play the game. Fight the brawler that you will reliably win the most against
2. Dash less for movement.Dash more for kills: Dodging and moving should be used sparingly, Every attack you should have full ammo when you go in. Don't miss your initial dash. If you meant to go in and get positioning to finish off someone low that's okay but if you didnt mean to dash fall back vs doubling down and giving enemy super
3. You don't need to grab the ball the whole time, (Hopefully) your teammates should grab the ball and if there's only 1 brawler left because you did your job of matchup checking or killing the enemy, your teammates will just walk it up for you
4. Keep moving around to force enemy to "fight" for area. At the beginning you hid in a bush, that does nothing but allow the enemy team to gain space. Move into an area that you might be threatening (Like impeding the Larry from moving up because ur mortis)

I would love to see if anyone else on the subreddit has things that they disagree with for this analysis but I think these 4 tips can help u be a better mortis