树莓派SSH连接华硕RT-AC1300G PLUS路由器失败：无互签算法问题求助

大家好，我最近碰到个SSH连接的难题，想请教下各位：

• 我用的是华硕RT-AC1300G PLUS路由器，之前在Windows PC上用ssh-keygen生成了RSA密钥对，把公钥配置到路由器的设置里（不管是web界面还是路由器的authorized_keys文件都确认存在），从PC连接路由器完全正常，没任何问题。
• 但换成树莓派连接的时候，一直弹Permission denied (publickey)，看debug日志的话，会显示debug1: send_pubkey_test: no mutual signature algorithm。
• 我试过把PC上能用的密钥对复制到树莓派上用，结果还是一样的错误；甚至直接在树莓派上重新生成新的密钥对，问题依旧存在。
• 后来我还尝试用ed25519密钥，但路由器根本不接受，查了下才知道Dropbear在2019.78版本还没支持ed25519，这也说得通。

下面是各设备的SSH版本信息：

• PC端ssh -V输出：OpenSSH_for_Windows_8.1p1, LibreSSL 3.0.2
• 树莓派端ssh -V输出：OpenSSH_9.2p1 Debian-2+deb12u1, OpenSSL 3.0.11 19 Sep 2023
• 路由器端ssh -V输出：Dropbear v2019.78

附上相关的debug日志片段：

PC连接成功的日志片段（执行ssh user@host -vvv） #

debug1: Offering public key: D:\\id_rsa_pi4router_pcgen RSA SHA256:toeuBlcfX2juW8AjDCntufrSvx9U1MRFcKNTmDBszEQ explicit
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: D:\\id_rsa_pi4router_pcgen RSA SHA256:toeuBlcfX2juW8AjDCntufrSvx9U1MRFcKNTmDBszEQ explicit

树莓派连接失败的日志片段（用同一密钥） #

debug1: Offering public key: /home/ndr/.ssh/id_rsa_pi4router_pcgen RSA SHA256:toeuBlcfX2juW8AjDCntufrSvx9U1MRFcKNTmDBszEQ explicit
debug1: send_pubkey_test: no mutual signature algorithm
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.

尝试ed25519密钥的日志片段 #

debug1: Offering public key: /home/ndr/.ssh/id_ed25519 ED25519 SHA256:LzXxVd/VRoB/QKE5OXjKk+pR69B2HT+x0nS/EfIRL3U explicit
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.

有没有大佬能帮忙分析下问题出在哪，怎么解决呀？谢谢大家！

备注：内容来源于stack exchange，提问作者Acat1728