Well...try to refer to Interface address lists like the other (apparently working ones) ?? Why do you select "ether1" and not "WAN" ? You tried and it doesn't work ?

You reference "ether1" for these Minecraft rules but that might be wrong. If you are using PPPoE for example to your ISP this probably will not work. This needs to be correct to start with.

Not too many people will reply without a export of relevant config, not just some screenshots.


EDIT : For some reason I cannot connect to my MC server from LAN or WAN. I am running the MC server on a separate device (192.168.50.4) then my main device (192.168.50.5)

You want to start with making a small drawing what you have constructed. What is "a separate device" ? Router ? Switch ?

viewtopic.php?t=179343

add chain=srcnat action=masquerade dst-address=192.168.88.0/24 src-address=192.168.88.0/24

dst-address-list=updatedCloudIP
add chain=dstnat action=dst-nat dst-address-list=updatedCloudIP address protocol=tcp dst-port=25550to-addresses=192.168.50.4

Correct hairpin nat!
Avoid quickset.
Yes every port forwarding rule has to be complete and having different ports will not interfere with each other.

Without seeing the full config will not comment.
However,

Port Forwarding requires a number of things
1. single port forwarding rule in the forward chain
add action=accept chain=forward comment="allow port forwarding" connection-nat-state=dstnat

2. If you have hairpin nat, users from same subnet as server require access to server via DYNDNS name or IP (instead of the direct local LAN IP). Then you need to ADD an associated sourcenat rule.
add chain=srcnat action=masquerade dst-address=192.168.88.0/24 src-address=192.168.88.0/24

3. Properly formatted DST nat rules for static or dynamic WANIPs.

4. If WANIP is dynamic and hairpin nat is involved one has to mimic the static case, as you have done with making the DYNDNS name an address list entry and using dst-address-list= in the dstnat rule.

5. The generic sourcenat rule for dynamic WAN does not change!!!

+++++++++++++++++++++++++++++++++++++++++++++++++++++++

Without seeding the config not sure what you have done wrong LOL. However you should have this rule in place as one of the sourcenat rules.
add chain=srcnat action=masquerade dst-address=192.168.50.0/24 src-address=192.168.50.0/24

[admin@MikroTik] > /ip firewall nat print 
Flags: X - disabled, I - invalid; D - dynamic 
 0    ;;; defconf: masquerade
      chain=srcnat action=masquerade out-interface-list=WAN ipsec-policy=out,none 

 1    chain=srcnat action=masquerade src-address=192.168.50.0/24 dst-address=192.168.50.0/24 

 2    ;;; Plex
      chain=dstnat action=dst-nat to-addresses=192.168.50.3 to-ports=32400 protocol=tcp in-interface-list=WAN 
      dst-port=32400 

 3    ;;; Plex
      chain=dstnat action=dst-nat to-addresses=192.168.50.3 to-ports=32400 protocol=udp in-interface-list=WAN 
      dst-port=32400 

 4    ;;; Plex
      chain=dstnat action=dst-nat to-addresses=192.168.50.3 to-ports=32435 protocol=tcp in-interface-list=WAN 
      dst-port=32435 

 5    ;;; Plex
      chain=dstnat action=dst-nat to-addresses=192.168.50.3 to-ports=32435 protocol=udp in-interface-list=WAN 
      dst-port=32435 

 6    ;;; UNRAID VPN
      chain=dstnat action=dst-nat to-addresses=192.168.50.3 to-ports=51820 protocol=udp in-interface-list=WAN 
      dst-port=51820 

 7    ;;; Minecraft TCP
      chain=dstnat action=dst-nat to-addresses=192.168.50.4 to-ports=25550 protocol=tcp dst-address-list=WAN IP 
      dst-port=25550 log=no log-prefix="" 

 8    ;;; Minecraft UDP
      chain=dstnat action=dst-nat to-addresses=192.168.50.4 to-ports=25550 protocol=udp dst-address-list=WAN IP 
      dst-port=25550 log=no log-prefix="" 

 9    ;;; HTTP
      chain=dstnat action=dst-nat to-addresses=192.168.50.3 to-ports=8181 protocol=tcp dst-address-list=WAN IP 
      dst-port=80 log=no log-prefix="" 

10    ;;; HTTPS
      chain=dstnat action=dst-nat to-addresses=192.168.50.3 to-ports=4433 protocol=tcp dst-address-list=WAN IP 
      dst-port=443 log=no log-prefix="" 

Dont quite understand but you have the correct hairpin nat rule.

YOur dstnat rules sucketh........
chain=dstnat action=dst-nat to-addresses=192.168.50.3 to-ports=32400 protocol=tcp in-interface-list=WAN
dst-port=32400

This is the wrong format? Are you sure you read the article?
For hairpin nat any interface=WAN is wrong, the traffic is not coming in from the WAN and thus right off the bat is logically wrong.

Please read again........ viewtopic.php?t=179343

Pay attention to; 1B

You have many options [ I prefer B (ii) ]
B (i), (ii), (iii), and 2.