[13] At the end of the year, MkLeo won the 2GGC Championship, this time defeating ZeRo in the finals, and claimed the tournament's $20,000 first place payout.

As ZeRo had long been considered the best Super Smash Bros. for Wii U player in the world, this created an opening for MkLeo to seize the top spot.

[2][15] He put together a string of impressive performances over the year, including wins at Genesis 5,[16] Evo Japan 2018,[17] CEO 2018,[18] Get On My Level 2018,[19] and SwitchFest 2018.

[21] These wins resulted in MkLeo taking the top spot in the final bi-annual Panda Global rankings of Wii U players before the release of Ultimate.

[28] Smash Ultimate was released in December 2018, and MkLeo had strong showings at several tournaments held shortly after the game's launch.

[30] MkLeo opened the second half of 2019 with a second-place finish at Smash Factor 8, held in Mexico, falling to Tyler "Marss" Martins.

[37] At Frostbite, after falling to Pedro "Prodigy" Alonso in the round of 96, MkLeo won the next 11 straight sets, defeating the 2nd, 3rd, 4th, 6th, 7th, 9th, 12th, 22nd, and 30th best players in the Panda Global rankings during his run to win the tournament.

[30] At Frostbite 2020, he played part of the grand finals match with Byleth, who had been released as a playable character in Ultimate only weeks earlier.

[42] In the second half of 2020, MkLeo began to use Byleth as his primary character and produced solid results placing top 8 in online tournaments.

MkLeo attended his first offline tournament since Frostbite 2020 at the SWT: Central America Ultimate Regional Finals, where he won the event without dropping a set.

MkLeo continued to place top 2 at every major event he attended, winning Riptide, Low Tide City 2021, Port Priority 6, and Mainstage 2021.

In March, he competed in the Smash Ultimate Summit 4 invitational, where he fell to Japanese player Protobanham in the Losers' Semifinals match.

[53] In April, he made a return to form by winning the Mexican invitational Delfino Maza's RETA 2022 as well as Genesis 8 over French player Glutonny.

[56][57] At August's Super Smash Con 2022, MkLeo fell to Angel "Onin" Mireles 0–3 in the first round of Winners' Top 32, before being eliminated by Glutonny in Losers' Quarterfinals.

[60] After Nintendo forced the Smash World Tour 2022 Championships to be cancelled, MkLeo dropped out of the Panda Cup Finale in protest and accepted Ahgren's invitation to play at his event, the "Scuffed World Tour", which was to be held on the same weekend as the Panda Cup Finale before it was indefinitely postponed.

On October 12, 2022, MkLeo revealed via Twitter that he had been experiencing lifelong ear-related health problems, but it had worsened to the point that it began to affect his hearing and ability to travel.

He subsequently dropped out of the upcoming Canadian tournament Battle of Z and took a break from competing that November, intending to prepare for the Smash World Tour 2022 Championships.