The first example can be written like this in Python >= 3.8:

    a = 1
    b = 2
    ((a := a + 1) if a == b else (b := b + 1)) + 1

although that's a lot to cram into a single line IMO.

The closest I could come up with for the second example is this (noting that the datetime constructor requires both the year and month):

    from datetime import datetime
    timestamps = [
        "2022:04:30:02:17:36",
        "2022:04:26:07:44:25",
        "2022:04:25:19:30:38",
        "2022:04:25:07:40:47",
    ]
    datetimes = [
        datetime(*map(int, timestamp.split(":")))
        for timestamp in timestamps
    ]

That said, it'd probably be better to use datetime.fromisoformat() or datetime.strptime() rather than manual parsing.

And you could maybe use the operator module[1] for the last example, like this:

    import operator as op
    (op.add if 1 < 0 else op.mul)(42, 100)

[1] https://docs.python.org/3/library/operator.html