Netplan: How to set the queue length of a network interface?

I’ve got a cluster of four machines running Ubuntu 24.04.4 LTS and now would like to increase the queue lengths of their respective network interfaces. As Netplan is running on all the nodes, and Google’s AI suggested me to add the parameter tx-queuelen in the Netplan config file /etc/netplan/01-netcfg.yaml:

network:
  version: 2
  renderer: networkd
  ethernets:
    pci0:
      dhcp4: yes
      tx-queuelen: 20000

But:

mixtile@blade3n1:~$ sudo netplan apply
/etc/netplan/01-netcfg.yaml:7:7: Error in network definition: unknown key 'tx-queuelen'
      tx-queuelen: 20000
      ^

So Google’s AI was wrong here. I also tried qlen, but no use. This is what ip addr show tells me:

mixtile@blade3n1:~$ ip addr show
6: pci0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65202 qdisc fq_codel state UP group default qlen 1000
    link/ether 02:9f:f1:8e:cb:0a brd ff:ff:ff:ff:ff:ff
    inet 10.20.0.11/24 metric 100 brd 10.20.0.255 scope global pci0
       valid_lft forever preferred_lft forever
    inet6 fe80::9f:f1ff:fe8e:cb0a/64 scope link 
       valid_lft forever preferred_lft forever

And 1000 seems to be not enough for my cluster. So: What’s the correct argument?

Update: After another user’s hint, I dug into the network status of pci0 and found an error I can’t explain:

mixtile@blade3n4:~$ networkctl status pci0

● 6: pci0
                   Link File: /usr/lib/systemd/network/99-default.link
                Network File: /run/systemd/network/10-netplan-pci0.network
                       State: routable (configured)
                Online state: online                                         
                        Type: ether
                        Path: platform-fe150000.pcie
                      Driver: miop-ep
            Hardware Address: 02:a4:f1:25:38:0a
                         MTU: 65202 (min: 68, max: 65202)
                       QDisc: fq_codel
IPv6 Address Generation Mode: eui64
    Number of Queues (Tx/Rx): 1/8
                     Address: 10.20.0.14 (DHCP4 via 10.20.0.1)
                              fe80::a4:f1ff:fe25:380a
                     Gateway: 10.20.0.1
                         DNS: 10.20.0.1
              Search Domains: lan
                         NTP: 192.168.178.1
           Activation Policy: up
         Required For Online: yes
             DHCP4 Client ID: IAID:0xdc41c1f2/DUID
           DHCP6 Client DUID: DUID-EN/Vendor:0000ab11b67fcf3e078bb454

Apr 17 19:50:33 blade3n4 (udev-worker)[498]: pci0: /etc/udev/rules.d/90-txqueuelen.rules:1 Failed to write ATTR{/sys/devices/platform/fe150000.pcie/net/pci0/qlen}, ignoring: No such file or directory
Apr 17 19:50:33 blade3n4 systemd-networkd[620]: pci0: found matching network '/run/systemd/network/10-netplan-pci0.network', based on potentially unpredictable interface name.
Apr 17 19:50:33 blade3n4 systemd-networkd[620]: pci0: Configuring with /run/systemd/network/10-netplan-pci0.network.
Apr 17 19:50:33 blade3n4 systemd-networkd[620]: pci0: Link UP
Apr 17 19:50:54 blade3n4 systemd-networkd[620]: pci0: Gained carrier
Apr 17 19:50:54 blade3n4 systemd-networkd[620]: pci0: found matching network '/run/systemd/network/10-netplan-pci0.network', based on potentially unpredictable interface name.
Apr 17 19:50:54 blade3n4 systemd-networkd[620]: pci0: DHCPv4 address 10.20.0.14/24, gateway 10.20.0.1 acquired from 10.20.0.1
Apr 19 14:30:03 blade3n4 systemd-networkd[620]: pci0: Gained IPv6LL