Lauterbrunnen to Lake Como- what’s the best way?

Long trip and a lot of train changes. Use the DBahn website. I don't think you'll be sent to Lucerne or Zurich because those are north. You need to go South to Milan.

"Lake Como" is a reverse-Y-shaped lake served by two different train lines - 1. Milan to Como and the to Lugano and Gotthard area; 2. Milan to east coast and then Tirano. As Switzerland has two important north-south (Lotschberg and Gotthard) connections but is poor of east-west connections, itineraries to Como may be through Lucerne or Milan (but Milan looks faster); itineraries to Lake Como east coast are possible only through Milan.

The rail hub for the Lauterbrunnen Valley is Interlaken.

Coming down the hill to Interlaken you have a choice. If you go west to Spiez you can get a train to Domodossola or Milan, possibly changing trains in Brig on the way. If you go east (via Brünig) over the extremely scenic cog wheel train to Luzern (German spelling of the English spelled Lucerne) you can get a train there to Como and Milan. In Milan you can get a train to Varenna-Esino for the middle part of the lake.

Either way, the mountains prevent you from going due south, you have to go around the mountains, and then the lake is large and you have to go around.

As the others say, Lake Como is a big lake, and it depends on where on the lake you are heading for.
Can you tell us which town you are heading for? Does it have a station, or where is the nearest station?
If it does not have a station, there are usually boats and buses from whichever is the nearest town with a station.

"The research I’ve done makes it seem like I need to go to Zurich or Lucerne to catch a train to Lake Como." - no way you need to go via Zürich, where have you been doing your research?

Look on the SBB (Swiss Railways) website: https://www.sbb.ch/en/
Enter Lauterbrunnen to whichever town you want to get to (must have a station), and date and time. This will find the quickest route.

If your destination is Como town or thereabouts, the route via Spiez and Milan is fastest.
If your destination is mid-lake, like Menaggio, Varenna, or Bellaggio, going via Luzern to Lugano then taking a bus to Menaggio will be equivalent to the route via Milan, and more scenic.
Combine the information from SBB (Swiss railways) with that from Navigazione Laghi (for Como ferries) to plot your route.

Thanks everyone. I’m staying at the southernmost point of the lake, near “Como”.