Why do you have a Moca filter inline? Are you using Moca?
Where is your LTE filter? It should be BEFORE any amplification.
An 8-way splitter is made up of a combination of SEVEN 2-way splitters. The result is approximately 10.5bB of loss at each port. A 4.5dB “boost” isn’t even making up the signal loss of the splitter.
Are all 8 ports of that splitter in use? If not, are the unused ones capped (terminated)?
I have towers at 8 miles and towers at nearly 40 miles. 45 degrees apart. My antenna has a 45 degree beam width. I have an older Clearstream 4 aimed toward the distant towers and kind of catching the near ones off the side with a 16dB preamp at the antenna. NOT aiming at the near towers is keeping me from over driving tuners with that amp in there. I’m split to 6 devices in the house with no distribution amp currently. If your antenna is amped, AND you have that distribution amp in there, you have to be conscious of the possible consequences of amping an already amped signal. If they’re more than 50 cable feet apart, it’s probably less of an issue (at least that’s been my experience). The point is, if you want to use OTA, that antenna, whichever one you use, is a critical component.
And as simple as some OTA proponents make this sound, it can be anything BUT simple.
I don’t personally have much faith in the so-called “multidirectional” antennas for TV. I see them as kind of like the fax/scanner/copier combinations that don’t seem to be very good at any of those 3 things. At 13 miles, though, you should get decent reception with a coat hanger (kidding).