I think the wrongs of the past should be recognised, the fact that imperialism has left all sorts of problematic legacies that impact on future generations is something those in power wouldn't have considered, but foresight is always lacking when borders are drawn up in the sand without any consultation. Apologies however imo cannot be on behalf of the nation only on behalf of the government that presided at the time those atrocities were committed and of course they were of their time. The population of the imperial powers of Europe were almost certainly disenfranchised and had no say in how their country was run, all their efforts went into staying alive I imagine.
An analogy can be made right now to a certain extent, so many Russians risk being imprisoned whilst they are vocally protesting about this ghastly war at pains to draw attention to the fact that this act of aggression engineered by Putin isn't done in their name. However, on a slightly different note, there are many religious institutions for example who need to go on apologising in perpetuity having swept so much under the carpet.
I think wrongs and ills remain relevant whilst people who suffered under them and possibly the next generation who carry the scars of their parents' traumas are still alive. Eventually The Holocaust for example, like other horrors will pass into the mists of time and be part of history. Sadly some atrocities get forgotten quite easily, does anyone remember the genocide the Armenian people suffered at the beginning of the 20th century.?
The past is littered with barbarism. Of course burning people at the stake as witches or for religious beliefs is beyond awful, but apologising really how futile is that! A leader can say all the mea culpas they like on such an issue but it will never change what's been done. Learning about the bigotry, prejudice, misogyny that shaped those beliefs of course but no one today played a part in those terrors. The other question is how far back do you go because eventually we almost celebrate the fact that we were conquered by so many, who hasn't been thrilled when as nation we find artefacts left behind by Romans and Vikings say, but the indigenous populations who were being subjugated and murdered by those invaders probably weren't thrilled living through it.
The past has gone, horrifically slavery hasn't so many people trafficked and abused in our time now. Read a shocking report recently about the young immigrant men working out in the UAE treated so very badly denied enough water in searing heat they now have kidney failure as a consequence.