I decided to prune my Bitcoin core node to 25 GB. With the blocks that the node has in its data 
directory (the ones that were not deleted), does such a node support the syncing of other nodes in the network? Moreover, let us imagine a new node that has just joined the network, let's say that has managed to download the first 10GB of data with his pruning set to 25GB. In such an early state, before pruning kicked in, does such a node serve the subset of the blocks that it has to the network?

Let the scope of this question be limited to the issue of syncing the blockchain data. I'm well aware of [the advantages of using a pruned node](https://www.reddit.com/r/Bitcoin/comments/9ztepo/does_running_a_5gb_prune_node_support_the_network/) as a wallet when compared to custodial services. There is already [a question somewhat relevant to the matter][3] and the answer to it suggests that as of May 2017, there is no way for pruned nodes to serve the subset of old blocks that they have. Is it still the case? Moreover, the answer to it does not refer to the second matter of serving a subset of blocks by a pruned node in which the pruning hasn't yet started. 
Although I came across some [resources][1] and [opinions][2] on pruning, none of them elucidated the matter of syncing to me.


[1]: https://bitcoin.stackexchange.com/questions/68849/how-could-the-bitcoin-protocol-be-modified-so-that-pruned-nodes-could-still-part
[2]: https://twitter.com/lopp/status/856152236874977280?lang=en
[3]: https://bitcoin.stackexchange.com/questions/53456/does-having-a-pruned-node-reduce-its-network-score