Terrain and proximity to the broadcast towers can really change the effectiveness and reliability of an antenna.
Back when I was recording HD OTA broadcasts I spent a good amount of time getting my attic mounted Channel Master 4228 positioned just right. Looks like they sell it now as the EXTREMEtenna 80.
https://www.channelmaster.com/products/extremetenna-80-outdoor-tv-antenna-cm-4228hd
I found that my local CBS station was the one that required the most attention during spring and fall. Placement that worked great would suddenly not get me a reliable signal when the leaves started dropping or coming in. Once they were gone or all the way on the tree my signal was great. I eventually found raising it just 2 inches more made all the difference and gave me a year round reliable signal.
In my case I am 40-50 miles from the broadcast antennas and the vast majority of the ATSC locals are(Well they were years ago) broadcast UHF. Your area might be all VHF, or a mixture, or like me mostly UHF.
That means your outdoor antenna might not be totally appropriate if it is one geared mostly to VHF or UHF and the channels are broadcast on the opposite spectrum.
But it could also be that your particular terrain requires an outdoor antenna for a quality signal. I helped a neighbor with an antenna and found that being lower on the other side of the street was just different enough that we could not get a reliable signal in the attic and needed to mount the antenna outside.
Something to research before running a cable. If it comes to that, you might just run the cable temporarily outside and in a window just to see before doing all the fishing.