How do I make lingering potion last longer?

I want to make the lingering potion particles last longer after it has been thrown. How (if possible) can I do this?

Solution 1:

You can't customise the cloud of a lingering potion after it has been thrown, although you can summon custom clouds without the lingering potion.

/summon minecraft:area_effect_cloud ~ ~ ~ {Radius:5,Duration:10000,Effects:[{Id:5,Amplifier:0,Duration:60}]}

Where the first duration is the time the cloud lasts in ticks, and the second duration is the time the potion effect lasts in ticks.

If you absolutely want the lingering potion to be thrown though, you could have one command block checking for potion clouds and removing them:

execute if entity @e[type=minecraft:area_effect_cloud] run kill @e[type=minecraft:area_effect_cloud]

then have another command block summon your custom potion cloud. The first command block would have to be deactivated quickly before the second one.