I remember when I could vote for the first time in 2012. I worked the polls that year because it sounded exciting, I got paid to do it (and of course, to a broke 18 year old, that's always important lol), and it was my first election I could actually vote in. Definitely a fun day. Long, but fun. I always heard on the news about lines being long and would see the footage of it, but of course, never experienced it myself because I never had reason to go to the polls before then, and my dad would always go first thing in the morning before he went to work to go vote, so he was always one of the first ones in and never dealt with the lines. There were people lined up outside first thing in the morning before the polls opened, and from 6am until 7pm when the polls closed, it was pretty much non-stop up until almost the end. Voted again in 2016, though didn't work the polls because I was in university then and had classes on the day of the election, but I went early in the morning with my dad to go and vote, and there was already a bit of a line when we arrived, and I'm sure it was busy all day.
I think COVID changed a lot with the voting process. I remember mail in ballots, early voting, and provisional votes being a thing even when I first started being able to vote, but it was never really as prominent as it seems to be now. I went and voted in 2020 for the primaries, and went in the late afternoon, early evening after work, and I was in and out within minutes. Didn't chalk it up to much since I'd always heard not as many people voted in the primaries compared to the actual day of the election. I went back for the presidential election later that year, and again, I was in and out within minutes because there was no line. That weirded me out more, but I figured more people took advantage of mail in ballots because of the pandemic.
I've moved to a new city since the 2020 election and voted in an election at my new precinct on a non-presidential year, but I didn't think anything of the precinct not being busy because it wasn't a presidential election. It took me longer to walk there than it did to cast my vote. Went again on Election Day this year, fully expecting to have to wait in a long line in the early afternoon when I went, and as I walked down my street towards the school where my precinct is, it was easy to see there wasn't many people there voting. I was surprised to just be able to walk over, walk right into the building after chatting with one of the campaigners outside for a moment, and not have to wait in a line to check in and get my ballot. Definitely was not what I was expecting.
I don't really feel like the early voting and mail in ballots really affects the counting process too much. The race was called early Wednesday morning, and even when I went to bed around 2-3am, the race hadn't been called, but I felt like there was a pretty clear winner at that point. I'm on the east coast, so even though the polls close at 7pm here, the last polls in the US don't close till 1am (Alaska, I'm looking at you), so I feel like I'm generally staying up that late anyways to get an idea of who's winning the race. Could the process as a whole be faster? Sure, but either way, I'll be up late waiting for a result because I'll still be waiting on states on the other side of the country to close their polls, so I think there's only so much faster they could make it go, at least until they can find a way for us to vote with the internet (which, as others have said, is a long ways away).
As for poll workers, I feel like I always saw the same ones at my old voting precinct. I got to know them a little better just because I worked with them during the 2012 presidential voting, but even when I went back in 2016 and 2020, it was still the same faces for the most part. At my current precinct, I think I've seen different people in the two times I've gone, but I've never really felt like there's been an issue with not enough staffing, at least at the polls.