Learn Hardcore Russian: Хоть бы основу выровняли сегодня.

Very often хоть бы sounds emotional: the speaker wants something to happen, sometimes because they are tired of waiting or worried it will not happen.

It does not literally mean even though here. In other contexts, хоть can mean other things, but in this pattern хоть бы + past tense form it expresses a wish.

Why is выровняли in the past tense if the speaker is talking about today or the future?

This is a very common Russian pattern.

After хоть бы, Russian often uses a past tense plural form to express a wish about the present or future.

So although выровняли is formally a past tense verb, here it does not mean that the action already happened. Instead, it works like:

if only they would level
I wish they’d level

This is similar to how some languages use past forms for unreal or wished-for situations.

So:

выровняли = literally past plural form
but in this construction = desired future result