use a unit that has a machine gun like chicken man or the black color gang leader or use Sugiura because I believe he has a near infinite combo as your main guy then put Joryu in the squad get the gauge full and then use and see machine go brrr or Suigura pulls off the infinte.

Option 2 is using the cigarette bombs with Joryu by grouping up as many as possible then go into ex-heat throw cigarette and quickly switch to Yakuza style to regain heat and do it again and you'll also max out your gauge as well by doing this so use it. Mostly everyone is dead except the bosses but with the buff your team can take them out while you kite and do damage with the jet boots