Removing the burning isn’t actually the way to go. The whole point of the guardian burn build is to apply single ticks of 1k+ damage each as frequently as possible so that it can’t be removed. There’s a few ways guardians will apply it, so you can start to look for it.
1. Blocking. Defender’s flame is an excellent way to apply burning with each block. That being said, it means you want to shorten the fight so they get as few blocks in as possible and avoid shelter. If they’re crafty they’ll run Runes of the Guardian which means 2 seconds of burning per block. This is probably the most deadly of the sources.
2. Judges intervention. It really can’t be countered, but if they teleport you should condi cleanse since JI has a decently long duration of burning.
3. Cleansing Flame. It’s a fairly obvious combo field. Dodge out and cleanse as soon as you can.
4. Virtue of Justice. There’s three ways they may use gw2 gold.
a. Standard way – every kittens (sometimes 3 hits, but it’s hard to pull off since they lose meditation heal or the crutch of the build the 33% burn dmg.)
b. AoE around them with Permeating Wrath. Stay at ranged.
c. Actually activating it. If you see their virtue of justice flash, it’s coming.
In all, it’s a tough build to beat since it’s based around blocking and surviving to deal burning. Using ranged burst, either power or condi is probably the way to go. It’s going to be a tough fight to out bunker them but it can be done.
Tl;dr; bursting, staying at range and keeping the fight as short as possible. Don’t focus on removing the burning, it’s only suppose to tick once or twice.