Option 1: Take the plunge as a DM, announce before hand that you’re new at this. Everyone who thinks they can do better is free to give it a try.
Option 2: Local Game Store.
Option 3: reddit /r/lfg. Google how to turn a search into an RSS stream, set up a search, be ready to jump into worthwhile-seeming posts quickly. Be ready to go through a few bad/mediocre groups until you find something that clicks.
My players loved and hated it both, but made it through without any deaths (a few death saves, though) and even got the Lich proper.
I literally ran this for my group just now.
Background was a cave system with very limited resources (previously few dead bodies to spare) and the Lich was both rather low on the power scale and Artificer-themed (so no "just spellcasting the party to death) and a Kobold.
So he fought/thought more like an engineer, not a powerful necromancer.
Highlights included:
Lair filled with Carbon Monoxide (I let the party notice symptoms and retreat, it was more of an area dental tool than a trap)
freezing the flooded exit tunnel so the party had to tunnel through ice, making them vulnerable to an ambush
installing an artifact that would flash-freeze said flooded tunnel with the party inside
a “main entry” labyrinth to the lair that was rigged to collapse
a side entry with a hidden, massive door that tried to crush the party and did manage to separate them
one-time sigils that would create a zone of Web, Darkness and, again, flash-freeze the intruders (and the undead defenders delaying them)
a remote body with his true body walled off in a tunnel behind the wall it can escape even if it loses
a few, highly upgraded undead
A smart player will try to keep the owl out of LoS during most of the round, so sacrificing action + reaction for “I attack it once it comes out of cover” is the best most NPCs can do.
Fly-By helps against opportunity attacks, but not against readied attacks.
Which, to me, is fair, because readying attacks requires the foe to sacrifice their main action and reaction.
When I DM, I always keep the idea in my back pocket that an enemy that has been distracted by a familiar too often will ready an attack to get rid of it the next time it is in range.
It’ll still eat their action, might miss, and I telegraph it sufficiently that an attentive player might adapt their familiar’s behavior, but it’s a thing that can mix up combat and keeps players on their toes.
I don’t know about you, but to me, the fact that he showed genuine humility and willingness to step beyond his initial chauvinism (after some hands-on lessons about fighting women) had a lot more to do with that than his charm.
The buff persists across stat increases.
You don’t see it in the level-up-screen, but it’s applied afterwards.
It’s easy to test:
Make a save, Withers, eat the hair, level up.
MH can only throw items that are on the ground.
If you drop some items on the ground from your inventory, MH can throw them without it requiring your action.
Thrown healing potions can revive/heal teammates.
Water bottles will make enemies vulnerable to lightning/frost spells/arrows.
A lit candle can be moved to stay close to anyone needing to dip.
Telekinesis. It’s not even a context
Telekinesis (especially at the “multiple tons” level) is an extremely flexible tool, a weapon, and a defense. There’s an endless amount of creative stuff you can do with it.
It can also still be used somewhat discreetly which is important.
Flight would probably be the most fun, though.