@allanfelipe I figured out the problem. It's because Opera is somehow doing memory-heavy writing routine to the History file in the Opera folder. When I deleted the entire (maybe a month-long) History, the file went from 6 Mb to 160 Kb, and the deleting speed dropped to nearly zero. This sort of issue has not been a problem until the start of this year or later, which means Opera has started to employ a new routine that now causes it. I outright ask them to fix it, dammit.

As of somewhat recently (maybe a month, not sure), manual selective History cleanup became a stupidly annoying chore, because even single-entry deletion takes some 3 seconds per entry, and if I use a Search function to separate a group of entries, their deletion literally makes the entire PC overclock as if it's using up most of my Memory to do so.
Note: This is not caused by me having a months-worth clog of History. I deliberately checked it on a cleanly wiped History, and there was almost no difference, especially for the Search-related nonsense.
Also, Opera is known for years to be a Memory-eater for no valid reason, so I fully suspect it being yet another such bug.

@vegelund
I'm the one who posted the "History deletion" complaint several months ago. I was told that it is fixed in Opera 100+... except it isn't. You still have to manually clean up your (bloated) History to remove that lag. This is clearly a coding issue, no doubt there (it strictly depends on the size of the History file alone, which is extremely visible via testing), but somehow nobody cares to even try investigating it, let alone actually fixing it. Nice support we have here, don't we? I mean, it's not like we have people complaining about the genius decision to "update" the general "theme" as well, no?

@mrmilesmano
Note: This is the Opera Forum... So, yeah. Nice, nice.
Good question: Why am I still using it? I mean, nostalgia and esthetic conditioning, yes, but why really?

@burnout426 Well, that was how many months ago? Great devs are great. Riiight. Are they trying to make us stop using Opera, eh?

@burnout426 I know how to get it back. I'm just pointing out that it's a bug anyways, and should be fixed.

More often than not, the Download button in the address bar tab disappears at random times for unknown reasons, and I mean it during or after finishing a download action. Makes literally no sense, is random, and I don't see any setting related to this (not that it'd be random in such a case). Any solution, or as always?

@vegelund
I'm the one who posted the "History deletion" complaint several months ago. I was told that it is fixed in Opera 100+... except it isn't. You still have to manually clean up your (bloated) History to remove that lag. This is clearly a coding issue, no doubt there (it strictly depends on the size of the History file alone, which is extremely visible via testing), but somehow nobody cares to even try investigating it, let alone actually fixing it. Nice support we have here, don't we? I mean, it's not like we have people complaining about the genius decision to "update" the general "theme" as well, no?

@superkoshej613
Still persists. Even the most newest update still "silently nudges" me to clean my History at least weekly, or the OP problem comes back. How about you actually fix the stupid coding that causes the number of entries to be a problem to begin with? Because if it was just a text file, I'm pretty sure there would NOT be ANY delays or problems. So who needs this dumb encoding anyways? I sure don't.

@allanfelipe Or at least they should Read and Reply, well, Here, ya know. I've posted my own complaint about this History issue a month or two ago - and I'm yet to receive a single response that Wasn't "well, then just delete your entire History". Nope, it's Broken (their fault), not Overloaded (my fault). That's literally just dodging the actual problem. Annoys me a lot, mind you.

@allanfelipe It's not "nice", because it forces me to choose between "empty History" and "easily deleting specific entries". And also because the sole reason behind this is some shitty encoding that only got introduced recently in the first place. So, no, not "nice" at all.

@allanfelipe I figured out the problem. It's because Opera is somehow doing memory-heavy writing routine to the History file in the Opera folder. When I deleted the entire (maybe a month-long) History, the file went from 6 Mb to 160 Kb, and the deleting speed dropped to nearly zero. This sort of issue has not been a problem until the start of this year or later, which means Opera has started to employ a new routine that now causes it. I outright ask them to fix it, dammit.

@edvardius
Same problem, more or less. Basically, it looks as if it's writing to the file in some way that overclocks the PC in a way that has never happened before some of the recent updates. So it's clearly a bug, but I don't see the developers caring about it whatsoever. Also, it's a proven fact that it is related to the amount of current History, because I wasn't getting it for a day or less after a clean History wipe, but then it came back at an increasing length with each additional day of History. This is very suspicious and/or very buggy. I suggest the developers to actually address it, instead of deleting my complaints. And yes, this involves editing this post to remove the actual complaint. It's outright dishonest to do so, ya know.