Is there any way to speed up actions in XCOM 2?

The mod "Stop Wasting My Time" (made by someone who is also active here, btw) would be just what you need. It removes unnecessary waiting times in the game, speeding your turns (and probably even the enemies turns) up significantly. Note however, that not all pauses in the game could be eliminated, as some of them are hardcoded into the game.

I use the mod myself, and I am totally happy with it.

Beware, though: as with all mods, deactivating the mod (should you decide you dont like it) prevents you from loading a save made with that mod. There is an experimental mod to "fix" this, but I would still recommend to Backup your saved game before installing any mod!

In addition to Stop Wasting My Time (made by a very mysterious and handsome author) already mentioned, there are a few other time-saving mods I highly recommend:

• Instant Avenger Menu: Instantly move between rooms in the Avenger. Also speeds up Avatar Project updates.
• Evac all: Adds a button to evac all units at once, rather than having to do it one-by-one
• Overwatch all: Same, but for Overwatch.
• Strip Primary Weapons: Adds a button to remove all weapons from all non-mission soldiers before a mission.
• If you like to color-code your soldiers by class, Automatically Color Units or Character Pool Uniforms will save you time.
• No Startup Movies: Skips the movies at the start of the game, speeding up the initial load time.
• Always Show Shot Breakdowns: Saves you from having to click the left-arrow on the attack screen all the time (which is actually a bug)

Also, the "experimental mod" mentioned by the other answer, Ignore Missing Content Warning, allows you to force-load a save game created with mods that are no longer installed. You wouldn't want to do this with any mods that add actual content (new flags/models/weapons/classes etc.), but all of the mods listed here should be togglable at will.

Not in-game actions, exactly, but there's currently an undocumented feature that lets you skip loading times after missions (i.e., the ones where everyone is sitting on the dropship heading back to base) just by pressing Caps Lock.

"Hitting the key, through a Rube-Goldberg-esque series of events, forces all outstanding load requests to be filled immediately in a single frame. This causes a massive hitch, and potentially could crash the game. If you don’t care about those adverse effects the synchronous load is faster." (developer at Firaxis)

I tried it last night, and it did shorten the loading to a couple of seconds. Just be aware that, as Firaxis says, this could possibly crash your game, so make sure you have autosaves turned on if you do this.

Incidentally, I found out about this while searching for information on the Lock and Load continent bonus, which I hope becomes the official name of the feature.