@sponkly This string a part of the Google cookies, I'm not sure how you get and how you want to use, in this case I give you an answer "as your question".
There are many possible way to get the value, I show you one of them.
We need to convert into JSON object, but for this we need to add "[" for the start and "]" at the end of your string, then convert into JSON object. After that you can access like an array element, in this case [0].value
Here is a short code example:
BAS:[{"name":"","code":"/*Dat:eyJzIjoic2V0dmFyaWFibGUiLCJ2IjoxLCJmIjpbXSwidXciOiIwIiwidXQiOiIwIiwidXRvIjoiMCIsInVtIjoiMCIsImQiOlt7ImlkIjoiU2V0VmFyaWFibGVOYW1lIiwidHlwZSI6InZhciIsImRhdGEiOiJDT09LSUVfU1RSSU5HIn0seyJpZCI6IlNldFZhcmlhYmxlVmFsdWUiLCJ0eXBlIjoiY29uc3RyIiwiZGF0YSI6Ilt7IFwiZG9tYWluXCI6IFwiZ29vZ2xlLmNvbVwiLCBcImV4cGlyZXNcIjogMTY2Njk1NjI2Ny41MjIwMDAxLCBcImh0dHBPbmx5XCI6IHRydWUsIFwibmFtZVwiOiBcInNlc19pZFwiLCBcInBhdGhcIjogXCIvXCIsIFwic2VjdXJlXCI6IHRydWUsIFwidmFsdWVcIjogXCJYQzVqSW05Z05UMDJjQ0RHcVpqZGpZbWMwWVRoaVlUcyUyQk5UQmdZR0ZsWW5Rd0pHWm9iamxrSWo0eFlTOWhZalFvWXpjJTJCTnpWak4yY0NYU0FEVGMzWm1Bd1kySnZPalZTREFTV1NEbUk3T2pWbFlHRmhOV0p2TUQ5bU9HNUFEQVNEQVNHWTBaRFYwTjNCZ2IyTWliejgxYURabmJERm1QV05wWnpCaE0ySmdPMmcxTTJBeFlUQmllakI3XCIgfSwgeyBcImRvbWFpblwiOiBcIi5nb29nbGUuY29tXCIsIFwiZXhwaXJlc1wiOiAtMTA4MDAsIFwiaHR0cE9ubHlcIjogZmFsc2UsIFwibmFtZVwiOiBcIlN0aWNreVNlc3Npb25cIiwgXCJwYXRoXCI6IFwiL1wiLCBcInNlY3VyZVwiOiBmYWxzZSwgXCJ2YWx1ZVwiOiBcIjY0MjY0NTY1MjU0NTYyXCIgfV0iLCJjbGFzcyI6InN0cmluZyJ9XX0=*/\nVAR_COOKIE_STRING = \"[\\u007b \\u0022domain\\u0022: \\u0022google.com\\u0022, \\u0022expires\\u0022: 1666956267.5220001, \\u0022httpOnly\\u0022: true, \\u0022name\\u0022: \\u0022ses_id\\u0022, \\u0022path\\u0022: \\u0022/\\u0022, \\u0022secure\\u0022: true, \\u0022value\\u0022: \\u0022XC5jIm9gNT02cCDGqZjdjYmc0YThiYTs%2BNTBgYGFlYnQwJGZobjlkIj4xYS9hYjQoYzc%2BNzVjN2cCXSADTc3ZmAwY2JvOjVSDASWSDmI7OjVlYGFhNWJvMD9mOG5ADASDASGY0ZDV0N3Bgb2Mibz81aDZnbDFmPWNpZzBhM2JgO2g1M2AxYTBiejB7\\u0022 \\u007d, \\u007b \\u0022domain\\u0022: \\u0022.google.com\\u0022, \\u0022expires\\u0022: -10800, \\u0022httpOnly\\u0022: false, \\u0022name\\u0022: \\u0022StickySession\\u0022, \\u0022path\\u0022: \\u0022/\\u0022, \\u0022secure\\u0022: false, \\u0022value\\u0022: \\u002264264565254562\\u0022 \\u007d]\"","internal_label_id":"","dat_precomputed":null,"search_precomputed":null,"code_precomputed":null,"parentid":0,"id":750155891,"donotexecuteduringrecord":false,"is_selected":false,"color":"","is_fold":false,"fd":""},{"name":"","code":"/*Dat:eyJzIjoiSnNvbkNoYW5nZUZvcm1hdCIsInYiOjEsImYiOltdLCJ1dyI6IjAiLCJ1dCI6IjAiLCJ1dG8iOiIwIiwidW0iOiIwIiwiZCI6W3siaWQiOiJEYXRhIiwidHlwZSI6ImNvbnN0ciIsImRhdGEiOiJbW0NPT0tJRV9TVFJJTkddXSIsImNsYXNzIjoic3RyaW5nIn0seyJpZCI6IlR5cGUiLCJ0eXBlIjoiY29uc3RyIiwiZGF0YSI6IkpTT04iLCJjbGFzcyI6InN0cmluZyJ9LHsiaWQiOiJTYXZlIiwidHlwZSI6InZhciIsImRhdGEiOiJDT09LSUVfU1RSSU5HX0pTT04ifV19*/\ntry {\nVAR_COOKIE_STRING_JSON = JPath.changeFormat(VAR_COOKIE_STRING, \"JSON\");\n} catch (e) {\nfail(e);\n}","internal_label_id":"","dat_precomputed":null,"search_precomputed":null,"code_precomputed":null,"parentid":0,"id":453751570,"donotexecuteduringrecord":false,"is_selected":false,"color":"","is_fold":false,"fd":""},{"name":"","code":"/*Dat:eyJzIjoic2V0dmFyaWFibGUiLCJ2IjoxLCJmIjpbXSwidXciOiIwIiwidXQiOiIwIiwidXRvIjoiMCIsInVtIjoiMCIsImQiOlt7ImlkIjoiU2V0VmFyaWFibGVOYW1lIiwidHlwZSI6InZhciIsImRhdGEiOiJDT09LSUVfU1RSSU5HX0pTT05fRUxFTUVOVCJ9LHsiaWQiOiJTZXRWYXJpYWJsZVZhbHVlIiwidHlwZSI6ImNvbnN0ciIsImRhdGEiOiJbW0NPT0tJRV9TVFJJTkdfSlNPTl1dWzBdLnZhbHVlIiwiY2xhc3MiOiJleHByZXNzaW9uIn1dfQ==*/\nVAR_COOKIE_STRING_JSON_ELEMENT = VAR_COOKIE_STRING_JSON[0].value","internal_label_id":"","dat_precomputed":null,"search_precomputed":null,"code_precomputed":null,"parentid":0,"id":879749111,"donotexecuteduringrecord":false,"is_selected":false,"color":"","is_fold":false,"fd":""}]