Build now or wait until more equity is available?

Before I come down hard, live life first before you commit yourselves firmly to a loan and a house, which no questioner in their twenties wants to hear here anyway, as it means too much paternalism to some, just read for yourself:

we have considered perhaps e

possibly even a building plot (gifted)

which we could have

however still considering whether we want to move there

We are quite uncertain

That doesn’t sound very convincing. Would, ifs and buts... maybe we could...
First become aware of what you really want. Then you can make something concrete with the gifted plot.
That is a decision that can also take a few years. That’s not bad, you are still young and not yet fixed in your opinion.

because we think it’s just wasted money

You can also see from this sentence – sorry – the maturity that has not yet developed. For a small contribution from your salary, you are allowed to live under one roof between four walls, and certainly not badly and without obligations. You also surely have heating.

Have support among friends who are very skilled with handiwork.

At your age, you should also have gained your own experience – you often can’t rely on friends, plus they have their own lives.

So take the next few years as a phase of exploration and read up on what costs building a house and after that actually entails.