Move liked videos from one Google Account to another, using YT Music

console commands.txt

// Get array of links which are videos/music from current YT music playlist.
const allLinks = Array.from($$(".yt-formatted-string")).map(x => String(x).includes("/watch?")? x.href : false).filter(Boolean)

//Reverse the same, so that the oldest item is on the top. This helps as we transfer this list to SeleniumIDE to automate and like the same videos in same order
allLinks.reverse()

//slice the last 8 chars from the strings, as they contain the playlis info. 
// If you keep this, the Like / dislike button will not be visible.
allLinks.map(x => x.slice(0,-8))

// Tip Copy the Object from Console! using right click
Then use seleniumIDE to loop through this list and like each of these videos. 
note we, remove like, then relike the video, in case it is already liked. This ensures we maintain history of likes. 

Selenium IDE .side file attached. 

Selenium.side

{
  "id": "d3bd1779-ae2d-4280-9097-59d19a749eb7",
  "version": "2.0",
  "name": "YT",
  "url": "https://music.youtube.com",
  "tests": [{
    "id": "7068f654-77ec-4f6e-bfd6-03c4d5a20a1c",
    "name": "1",
    "commands": [{
      "id": "995220d1-7b08-461f-8fa8-e1b8c3e81cb1",
      "comment": "",
      "command": "open",
      "target": "https://music.youtube.com",
      "targets": [],
      "value": ""
    }, {
      "id": "1c9c1561-6d5c-4d62-b71a-dbe579555533",
      "comment": "",
      "command": "executeScript",
      "target": "return [    ]",
      "targets": [],
      "value": "allLinks"
    }, {
      "id": "c6f9eda9-a3d5-4b1c-89d2-3e7f2e828484",
      "comment": "",
      "command": "echo",
      "target": "${allLinks.length}",
      "targets": [],
      "value": ""
    }, {
      "id": "d072d15c-0acb-43e8-83cb-d8dd69ccadab",
      "comment": "",
      "command": "store",
      "target": "0",
      "targets": [],
      "value": "countDone"
    }, {
      "id": "d2d0eec5-a290-4ea2-9fbf-5ac1fe19a185",
      "comment": "",
      "command": "forEach",
      "target": "allLinks",
      "targets": [],
      "value": "alink"
    }, {
      "id": "b8bd9015-6e2a-4d93-91a8-4071aa9fbe5f",
      "comment": "",
      "command": "executeScript",
      "target": "return parseInt(${countDone}) + 1",
      "targets": [],
      "value": "countDone"
    }, {
      "id": "f63dc939-693d-4897-9d9a-4d2a934807a4",
      "comment": "",
      "command": "echo",
      "target": "${countDone}",
      "targets": [],
      "value": ""
    }, {
      "id": "f1814734-ce6c-4577-ab16-246132f21fbb",
      "comment": "",
      "command": "echo",
      "target": "${alink}",
      "targets": [],
      "value": ""
    }, {
      "id": "75762776-ab96-4569-91c1-c049354c7e48",
      "comment": "",
      "command": "open",
      "target": "${alink}",
      "targets": [],
      "value": ""
    }, {
      "id": "52c97cf3-5117-46f0-8851-e4b67e9e7c3c",
      "comment": "",
      "command": "waitForElementVisible",
      "target": "css=.like > #icon",
      "targets": [
        ["css=.dislike > #icon", "css:finder"],
        ["xpath=(//tp-yt-iron-icon[@id='icon'])[119]", "xpath:attributes"],
        ["xpath=//ytmusic-like-button-renderer[@id='like-button-renderer']/tp-yt-paper-icon-button/tp-yt-iron-icon", "xpath:idRelative"],
        ["xpath=//ytmusic-like-button-renderer/tp-yt-paper-icon-button/tp-yt-iron-icon", "xpath:position"]
      ],
      "value": "30000"
    }, {
      "id": "1f1f71dd-8248-42c7-8ecd-9047b3c21ce3",
      "comment": "",
      "command": "storeAttribute",
      "target": "css=.like@aria-pressed",
      "targets": [],
      "value": "isLiked"
    }, {
      "id": "b4365288-2cc9-433a-9bb2-ed76ed6f8482",
      "comment": "",
      "command": "//echo",
      "target": "${isLiked}",
      "targets": [],
      "value": ""
    }, {
      "id": "96e37f83-e498-4696-ae41-9fb4b95af7c4",
      "comment": "",
      "command": "if",
      "target": "${isLiked} === \"false\"",
      "targets": [],
      "value": ""
    }, {
      "id": "4c12f20e-ec93-4967-a451-601510b391f6",
      "comment": "",
      "command": "click",
      "target": "css=.like > #icon",
      "targets": [],
      "value": ""
    }, {
      "id": "f838bd8f-b344-42d8-929a-0a4c15942e97",
      "comment": "",
      "command": "else",
      "target": "",
      "targets": [],
      "value": ""
    }, {
      "id": "69c300a2-b76e-4640-a7e9-8caf7acc4cdd",
      "comment": "",
      "command": "click",
      "target": "css=.like > #icon",
      "targets": [],
      "value": ""
    }, {
      "id": "7bae37f0-7b5f-422a-8af8-38fc1a49c840",
      "comment": "",
      "command": "click",
      "target": "css=.like > #icon",
      "targets": [],
      "value": ""
    }, {
      "id": "d2e397fc-9895-4fe3-9a46-deefab455d27",
      "comment": "",
      "command": "end",
      "target": "",
      "targets": [],
      "value": ""
    }, {
      "id": "a63ee849-5824-4eac-b6de-9bd28bab281a",
      "comment": "",
      "command": "end",
      "target": "",
      "targets": [],
      "value": ""
    }]
  }],
  "suites": [{
    "id": "7ca6e23c-c5e7-440c-9492-7fb611c99a29",
    "name": "Default Suite",
    "persistSession": false,
    "parallel": false,
    "timeout": 300,
    "tests": ["7068f654-77ec-4f6e-bfd6-03c4d5a20a1c"]
  }],
  "urls": ["https://music.youtube.com/"],
  "plugins": []
}