What scenario occurs when local candiate is relay and remote candidate is prflx in ICE?

Question

To easily describe the problem, allow me to quote Figure 1 from RFC8656 (link: https://www.rfc-editor.org/rfc/rfc8656.txt ).

Assume that the current Client is unable to receive data directly from Peer A and Peer B, with turn's relay enabled.

I can understand that if Peer A or Peer B need to send data to Client, send the data directly to turn server's relay address (192.0.2.15:50000). Turn server will send (relay) the corresponding data to Client through the direct connection between Client and turn server.

What I want to know now is, if Client wants to send data to Peer A, will it be relayed via Turn Server or possibly sent directly via Prflx or Srflx (192.0.2.150:32102)? I will call this data as uplink traffic.

Based on efficiency and performance considerations, uplink traffic that can be sent directly to Peer A via prflx or srflx is definitely the better way (I call this way Direct). But since Peer A may not be reached directly due to NAT, then there are two ways to solve it:

one is using the exsisted Client assigned Relay, which is that 192.0.2.15:50000, I call this way OldRelay;

Another way is Peer A also use its own Turn Relay, that becomes another structure, I'll ignore this scenario.

To summarize, my questions are:

1. Are both the Direct way and the OldRelay way allowed?

2. If both Direct and OldRelay are allowed, what is the difference between the client's Candidate pair in these two cases? Or how to distinguish between these two cases from Candidate Pair?

=====================Updated===========================

In fact, there is a problem with my old question. Because if one direction can be served directly, then actually the other direction can be served directly as well. So there is no case of relay in one direction and direct delivery in the other.

I am not going to modify my original question, because there is already a user discussion for this issue and pointed out my mistake.

But I would like to say that my error comes from a strange state screencap: https://postimg.cc/F1wRM7Y5

I'm discussing this with @PhilippHancke, because as understood, if one can get the Prflx on the other end, then one should use p2p instead of relay.

Is this theoretically the case in the diagram (I've checked that there is no policy forcing the use of relay).

I'm also trying to figure out whether to use relay or p2p in this scenario.

Thank you very much~

                                       Peer A
                                       Server-Reflexive    +---------+
                                       Transport Address   |         |
                                       192.0.2.150:32102   |         |
                                           |              /|         |
                         TURN              |            / ^|  Peer A |
      Client's           Server            |           /  ||         |
      Host Transport     Transport         |         //   ||         |
      Address            Address           |       //     |+---------+
   198.51.100.2:49721  192.0.2.15:3478     |+-+  //     Peer A
              |            |               ||N| /       Host Transport
              |   +-+      |               ||A|/        Address
              |   | |      |               v|T|     203.0.113.2:49582
              |   | |      |               /+-+
   +---------+|   | |      |+---------+   /              +---------+
   |         ||   |N|      ||         | //               |         |
   | TURN    |v   | |      v| TURN    |/                 |         |
   | Client  |----|A|-------| Server  |------------------|  Peer B |
   |         |    | |^      |         |^                ^|         |
   |         |    |T||      |         ||                ||         |
   +---------+    | ||      +---------+|                |+---------+
                  | ||                 |                |
                  | ||                 |                |
                  +-+|                 |                |
                     |                 |                |
                     |                 |                |
            Client's                   |             Peer B
            Server-Reflexive     Relayed             Transport
            Transport Address    Transport Address   Address
            192.0.2.1:7000       192.0.2.15:50000    192.0.2.210:49191

                                  Figure 1