get all updatable fields from account and describe it for lwc

AccountService.cls

public with sharing class AccountsService {
    
    public string getAllFieldsAndValues(String accIdA, String accIdB) {
        final Set<String> systemFields = new Set<String> {
            'CreatedDate',
            'CreatedById',
            'LastModifiedById',
            'LastModifiedDate'
        };
        try {
            AllFieldsAndValues finalResp = new AllFieldsAndValues();
            Map<String, Schema.SObjectField> accountFieldByApiName = Schema.Account.SObjectType.getDescribe().fields.getMap();
            String getAccountValuesQuery = 'SELECT {0} FROM Account WHERE Id = {1} OR Id = {2}';
            String fields = 'Id, ';

            FieldDescription fDesc;
            for (String apiName: accountFieldByApiName.keySet()) {
                Schema.DescribeFieldResult fieldResult = accountFieldByApiName.get(apiName).getDescribe();
                fDesc = new FieldDescription();
                fDesc.isSystemField = systemFields.contains(apiName);
                if (fieldResult.isAccessible() && (fieldResult.isUpdateable() || fDesc.isSystemField)) {
                    fields += fieldResult.getType() == Schema.DisplayType.PICKLIST ? ('toLabel(' + apiName + '), ') : apiName + ', ';
                    fDesc.label = fieldResult.getLabel();
                    fDesc.apiName = apiName;
                    fDesc.type = fieldResult.getType().name();
                    if (fieldResult.getType() == Schema.DisplayType.Reference) {
                        fDesc.referenceNamePath = apiName.endsWithIgnoreCase('__c') ? apiName.replace('__c', '__r') + '.Name' : 
                            (apiName.endsWithIgnoreCase('__pc') ? 
                            apiName.replace('__pc', '__pr') + '.Name' :
                            apiName.left(apiName.length() - 2) + '.Name');
                        fields += fDesc.referenceNamePath + ', ';
                        fDesc.isReference = true;
                    }
                    
                    finalResp.fieldDescriptionByApiName.put(apiName, fDesc);
                }
            }

            String finalQuery = String.format(getAccountValuesQuery, new List<String> {
                fields.removeEnd(', '),
                '\'' + accIdA + '\'',
                '\'' + accIdB + '\''
            });

            System.debug(finalQuery);

            List<Account> accList = Database.query(finalQuery);
            finalResp.accountA = accList[0];
            finalResp.accountB = accList[1];
            
            return JSON.serialize(finalResp);
        } catch (Exception e) {
            throw new AuraHandledException(e.getMessage());
        }
    }

    class AllFieldsAndValues {
        public Account accountA; 
        public Account accountB; 
        public Map<String, FieldDescription> fieldDescriptionByApiName; 

        public AllFieldsAndValues() {
            fieldDescriptionByApiName = new Map<String, FieldDescription>();
        }
    }

    class FieldDescription {
        public String label;
        public String apiName;
        public String type;
        public Boolean isSystemField;
        public Boolean isReference;
        public String referenceNamePath;
    }

}