After upgrading to angular version 10 or 18.2.55, the peer dependencies in @syncfusion/ej2-angular-base have not been updated.
Taken from the package.json file for lib @syncfusion/ej2-angular-base
"peerDependencies": {
"@angular/common": "4.10.0 - 9.1.3",
"@angular/compiler": "4.10.0 - 9.1.3",
"@angular/core": "4.10.0 - 9.1.3",
"@angular/forms": "4.10.0 - 9.1.3",
"@angular/platform-browser": "4.10.0 - 9.1.3",
"@angular/platform-browser-dynamic": "4.10.0 - 9.1.3"
},