Do you believe the computer experts and hackers who have shown that they can hack into voting systems?
As Daisy points out, it depends on what you are talking about. Sure they "can" be hacked, as can any piece of electronics. The issue is that they largely can't be, in real life, as those that would hack them don't have the access to do it when it counts; there are various layers of security to protect that from happening.
To start with, the machines are physically secured. Next, they go through tests before the election occurs to ensure the machine is "secure" (hasn't been hacked). And a "hacker" isn't going to be able to take apart a machine (take of the cover or other pieces) to get in to replace chips, nor are these machines connected to the Internet. From what I know, there are also checks after the election to ensure the software remains intact (not hacked). There appear to be other ways to safeguard the machines that we don't have direct knowledge of, and these are kept "secret" as a further security safeguard.
On top of the security of the machine, the last I saw, any machines purchased now must create a paper copy, so the voter can verify their vote is correct. This is part of what happened in Georgia in 2020, where the state recounted the paper ballots -- that voters could verify -- to ensure the counts were accurate, even doing a hand recount of those paper ballots.
Yes, voting machines can be "hacked" but the likelihood of it happening during an election is very low, particularly any chance it would change the results. About the only way it could occur is when the director in charge of elections, along with several staff members, would have to be in on the "steal," and there are still several ways they could be caught. Of course, if you have this type of conspiracy to change the results of the election, then paper ballots are not going to be any more secure.