How can I redirect non API calls to angular routing with .NET6?

I had this problem where reloading a page on production (Azure Linux App Service) were throwing a 404.

I managed to fix this using hashLocationStrategy in my app.routing.module.ts. But it is not SEO safe. I understand that it works because the API ignores what's after the hash, but I was wondering how could I rollback this change on the routing strategy, and handle the redirection in my API.

I looked up for something on the Internet, but I didn't manage to find anything working. I tried using app.MapWhen() or modifying app.MapControllers() to app.UseEndpoints(options => options.MapControllers()). And the more I look up for this, the more I find it very confusing.

Here is my current Program.cs :

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddHttpsRedirection(options => options.HttpsPort = 443);

// Add services to the container.
builder.Services.AddCors(options => 
    options.AddPolicy("Default", policyBuilder =>
    {
        policyBuilder
            .AllowAnyOrigin()
            .AllowAnyMethod()
            .AllowAnyHeader();
    })
);

builder.Services.AddControllers();
builder.Services.AddAuthentication(x =>
{
    x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
}).AddJwtBearer(o =>
{
    o.SaveToken = true;
    o.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuer = false,
        ValidateAudience = false,
        ValidateIssuerSigningKey = true,
        IssuerSigningKey = new SymmetricSecurityKey(
            Encoding.UTF8.GetBytes(
                builder.Configuration
                    .GetSection(ApplicationSettings.Section)
                    .GetValue<string>("JWT:Secret")))
    };
});

builder.Services.AddSwaggerGen(config =>
{
    config.SwaggerDoc("Backend", new OpenApiInfo { Title = "Backend", Version = "0.1"});

    config.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme
    {
        In = ParameterLocation.Header,
        Description = "Please enter a valid token",
        Name = "Authorization",
        Type = SecuritySchemeType.Http,
        BearerFormat = "JWT",
        Scheme = "Bearer"
    });

    var securityRequirement = new OpenApiSecurityRequirement
    {
        {
            new OpenApiSecurityScheme
            {
                Reference = new OpenApiReference
                {
                    Type = ReferenceType.SecurityScheme,
                    Id = "Bearer"
                }
            },
            Array.Empty<string>()
        }
    };

    config.AddSecurityRequirement(securityRequirement);
});

builder.Services.Configure<ApplicationSettings>(
    builder.Configuration.GetSection(ApplicationSettings.Section));

builder.Services.AddDbContext<InstituteDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("Database")));

// Repositories
builder.Services.AddScoped<ICareCategoryRepository, CareCategoryRepository>();
builder.Services.AddScoped<ICareRepository, CareRepository>();

builder.Services.AddScoped<IUserRepository, UserRepository>();

builder.Services.AddScoped<IReservationInfoRepository, ReservationInfoRepository>();

// Services
builder.Services.AddScoped<ICareService, CareService>();
builder.Services.AddScoped<ICareCategoryService, CareCategoryService>();

builder.Services.AddScoped<IUserService, UserService>();

builder.Services.AddScoped<IReservationService, ReservationService>();

builder.Services.AddScoped<IReservationInfoService, ReservationInfoService>();

var app = builder.Build();

using (var scope = app.Services.CreateScope())
{
    var services = scope.ServiceProvider;

    var context = services.GetRequiredService<InstituteDbContext>();
    context.Database.Migrate();
}

app.UseMiddleware<ExceptionHandlerMiddleware>();
app.UseMiddleware<JwtMiddleware>();
app.UseMiddleware<AntiXssMiddleware>();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI(options =>
    {
        options.SwaggerEndpoint("/swagger/Backend/swagger.json", "Backend");
    });
}
else
{
    app.UseHttpsRedirection();
}

app.UseRouting();

app.UseCors("Default");

app.UseAuthentication();
app.UseAuthorization();

app.UseDefaultFiles();
app.UseStaticFiles();

app.MapControllers();

app.Run();

EDIT : Here is the .htaccess file I used (there is more than just url rewriting)

RewriteEngine On

# Redirection to HTTPS:
RewriteCond %{HTTPS} !on
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

# Redirection of requests to index.html
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -f [OR]
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -d
RewriteRule ^.*$ - [NC,L]
# Redirect all non-file routes to index.html
RewriteRule ^(?!.*\.).*$ index.html [NC,L]