What you say is true: starters are just for learning, or to form the basis of a legal deck for a local event or something. You say you are inexperienced at deckbuilding, but you've done pretty well so far I think. Making a fun deck from a limited pool of cards is always challenging, much less making two decks from the same pool that have to be at the same power level. If you've managed to get that far, regardless of how much help you've had along the way, you're as well prepared as anyone to go from there and experiment with your own decks. From the sounds of it, you may actually want one deck to be a little better than the other -- you use the worse deck, which would help balance the skill difference between someone who plays every few days and someone who plays every few months.
It's hard to know whether two decks really are balanced, but at a glance you can determine how close they are -- just compare what the cards can do. If one deck can only put out 9 strength minions while the other deck has 2 reliably 10-strength companions, you'll pretty easily be able to see how much twilight the first deck would need to be able to spend before having any impact at all. Similar checks can be made for wounds vs healing, burdens vs burden removal, conditions vs condition removal, how much strength the Ring-bearer can stand in a swarm, etc. Once you determine that they're close, though, the only way to see if they're truly balanced is to play lots of games with them.
But anyway, I'm a bit confused by the goal. You have a few pairs of decks that seem pretty good against one another, do you just want more? Starter decks intentionally don't have a lot of mechanics or even variety among them, so if you don't have a bunch of cards to build decks from and don't want to print, you're probably nearing your dead end. If you do have more cards (or are willing to print), the first resource I'll point you towards is Gemp's "Towers Standard Sealed" decks. They were made on these very forum boards by people who wanted to do something similar:
https://wiki.lotrtcgpc.net/wiki/TS_Sealed(The full history of them can be found at
https://lotrtcgwiki.com/forums/index.php?topic=9003.0 -- I haven't read through it, but I would assume it's got some very detailed explanations of what cards were and weren't included in these starter decks )
I've created about a dozen decks for King Standard (1-7) with the intent of printing them out and putting them in cheap sleeves on top of even cheaper cards and using them for introductory matches. Perhaps a Shadow or Free Peoples side here is of interest to you and could be adapted into a Towers Standard deck:
https://lotrtcgwiki.com/forums/index.php?topic=12134.msg99194A bit farther from where you're starting, you can look into seeing if you can create any parts of Dictionary's Clash Decks which were made to be mid-level decks in Expanded (all sets legal):
https://lotrtcgwiki.com/forums/index.php?topic=11731.0There may have been other initiatives in the past lurking around these boards somewhere. By searching
Starter Deck I see 14 pages of results. Most of these results are talking about existing starters or return posts where members happened to use the words "starter" and "deck" in the same post. However, I know at least some results are people attempting to create new starter decks that would be competitive additions (neither too strong or too weak) to the existing Decipher ones. Whether they hit or miss is something you'll have to find out, but it's better than starting from scratch.
Finally, if deckbuilding is still intimidating, look at these resources that ket_the_jet gathered together which showcase some competitive decks and in some cases go into detail about what makes them tick:
https://lotrtcgwiki.com/forums/index.php?topic=10820.msg92930Once you understand how to build a most competitive deck, making it a little less competitive is just a matter of using less efficient cards or diluting the deck's goals with other potentially-useful-but-not-crucial effects. Hobbit skirmish events in particular are very fertile ground -- they keep Frodo alive during skirmishes, but having too many of them will make it more necessary for Frodo to skirmish by weakening the rest of your deck.