I want to use OpenID Connect for all end users and use standard Episerver login for all editors.
Is there any way to accomplish this in Optimizely 12?

This is my current setup. Now everyone is moving towards the external provider. 
What I would like to achieve is that the url "/episerver/cms" uses the standard login.

services
            .AddAuthentication(options =>
            {
                options.DefaultAuthenticateScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
            })
            .AddCookie()
            .AddOpenIdConnect(
                options =>
                {
                    options.SignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                    options.ClientId = "####";
                    options.ClientSecret = "####";
                    options.Authority = "#####";
                    options.CallbackPath = "/callback";
                    options.ResponseType = "code";
                    options.GetClaimsFromUserInfoEndpoint = true;

                    options.TokenValidationParameters = new TokenValidationParameters
                    {
                        ValidateIssuer = false,
                        RoleClaimType = ClaimTypes.Role,
                        NameClaimType = ClaimTypes.Email
                    };

                    options.Events.OnAuthenticationFailed = ctx =>
                    {
                        ctx.HandleResponse();
                        ctx.Response.BodyWriter.WriteAsync(Encoding.ASCII.GetBytes(ctx.Exception.Message));
                        return Task.FromResult(0);
                    };

                    options.Events.OnTokenValidated = (ctx) =>
                    {
                        var redirectUri = new Uri(ctx.Properties.RedirectUri, UriKind.RelativeOrAbsolute);
                        if (redirectUri.IsAbsoluteUri)
                        {
                            ctx.Properties.RedirectUri = redirectUri.PathAndQuery;
                        }

                        //Sync user and the roles to EPiServer in the background
                        //ServiceLocator.Current.GetInstance<ISynchronizingUserService>().SynchronizeAsync(ctx.Principal.Identity as ClaimsIdentity);
                        
                        return Task.FromResult(0);
                    };
                });