No matter 1 or 1 billion non-mining full nodes, it has zero effect on decentralization, because all they do is relay, they don't validate ,
so this virtue is pure imagination on the part of bitcoiners, kind of you have to believe it to join the bitcoiner cult.
You're lucky that I'm ran out of demerits. Ever heard of
Sybil Attack? You are contributing to the harmony of the network if you run a full node. AFAIK, you aren't connecting on the same nodes each time you establish a connection, but a Bitcoin Core expert can correct me. There's that thing called peer discovery that
stimulates decentralization.
The fewer the nodes the worse the decentralization.
You seem more reasonable than the majority.

Here is why I think the way I do about the non-mining nodes not helping decentralization.
https://bitcoin.stackexchange.com/questions/50922/whats-a-sybil-attackSybil attacks are avoided in Bitcoin by requiring block generation ability to be proportional to computational power available through the proof-of-work mechanism. That way, an adversary is limited in how many blocks they can produce. This provides strong cryptographic guarantees of Sybil resilience.
Non-mining nodes can't generate new blocks. They only relay blocks generated by mining nodes.
What make BTC resistant to Sybil is that by segregating the evildoer's mining hashrate from the rest of the network, block propagating would stall without the rest of the network mining nodes hashrate.
All of the protection/security of Bitcoin network is from the Mining Pools and their mining nodes that generate blocks.
All a non-mining nodes does is provide the user with a local receipt copy of all transactions,
Here is an example to clear it up for you,
if I run 500 non-mining nodes from a different IP address is that more decentralized
than running 1 non-mining node. Trick question , because 1 or 500 neither generates blocks, so neither help decentralization.
If I run 10 mining nodes instead of 1 mining node, then the 10 mining nodes do increase decentralization.
If that makes sense to you , great,
if not, Have a Great Day anyway.
